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Lower to middle Jurassic (Pliensbachian to Bajocian) stratigraphy and Pliensbachian Ammonite fauna of.. Thomson, Robert Charles 1985-12-31

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LOWER AND  TO  MIDDLE  JURASSIC (PLIENSBACHIAN  PLIENSBACHIAN  AMMONITE FAUNA NORTH  CENTRAL  OF  TO  THE  BRITISH  BAJOC1AN) NORTHERN  STRATIGRAPHY SPATSIZI  COLUMBIA  by ROBERT CHARLES B.Sc,  UNIVERSITY  OF  THOMSON ALBERTA,  A THESIS S U B M I T T E D IN P A R T I A L THE  REQUIREMENTS  FOR  MASTER  OF  1981  FULFILMENT  THE  DEGREE  OF  SCIENCE  in THE  FACULTY  DEPARTMENT  We  OF  OF  GRADUATE  GEOLOGICAL  STUDIES SCIENCES  accept this thesis as conforming to the required standard  THE  UNIVERSITY  OF  BRITISH  OCTOBER, ®  ROBERT CHARLES  COLUMBIA  1985 THOMSON,  1985  OF  AREA,  In presenting at the  The  available  this thesis i n partial  for reference and study. I further  her  requirements for an advanced  University of British Columbia, I agree that the  this thesis for scholarly his or  fulfilment of the  purposes  representatives. It  may  be  is understood  agree that permission granted  by the  that copying  financial gain shall not be allowed without my written  DEPARTMENT  OF GEOLOGICAL  The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V 6 T 1W5  Date:  OCTOBER.  1985  Library shall make it  SCIENCES  freely  for extensive copying  Head of my Department or publication  permission.  degree  of  this  of  or  by  thesis  for  Abstract The  lithostratigraphy  Pliensbachian Group,  to  from  Bajocian  the  and  Pliensbachian  sedimentary  Spatsizi  rocks,  map-area  ammonite  informally  (104  H)  in  referred  the  thesis  rocks  area  of the  Spatsizi  determined.  The  Tethyan  aspect and also contains  Spatsizi  fauna  Cordilleran  Pacific  located  eugeocline,  ammonites northern  is  on  and  Spatsizi  described  fauna  is  northern  surrounded  half by  to  of  the  the  Spatsizi  Columbia  stratigraphic of  East Pacific  biogeographically  as  of  are  fifteen genera from  primarily  Stikine  sequence  British  and their  to the  a  here  representing  comprised  elements endemic  the  is  Group are  of  north-central  examined in this thesis. Twenty Five species of ammonites Pliensbachian  fauna  ranges i n  ammonites  faunal realm.  terrane related  of  the  faunas  of The  western containing  of Boreal affinity i n addition to Tethyan and East Pacific forms, indicating that Stikinia occupied a position within the mixed Boreal/Tethyan  region  during  the  Pliensbachian.  Subsequent  tectonic  zone of the  displacement  of  eastern Stikinia  transported it northward to its present position. The  Spatsizi  formations;  the  Group  Joan,  is  Eaglenest  informally  Gladys, Groves,  reflects deposition i n a  different  volcanic  pyroclastic)  (epiclastic  basinward the  sedimentary  southern  north  to  during  the  flank  equivalents  of  the  sedimentary  Pliensbachian  accumulating on the the  or  and  and  input  of  Rocks  the  coeval  Arch.  Facies  in the  Early  Toarcian  south  is  the  transitions  times,  best  when  flank of the arch  into  Formations.  affected  by  Spatsizi  Toodoggone  are  divided  Walker  environment  basin  Group  from the  epiclastic  Each  informal formation  varying degrees  volcanics  developed  five  represent  that  formed  Stikine  Arch  in  sediments  sands  and  of the  along in  the  deposited  conglomerates  graded southward into silts and muds in  basin. Two phases of non-coaxial  map  and  sedimentary  to  Stikine  southern  defined  area.  Deformation  was  North American continental  deformation  probably  related  margin during  folded and faulted the rocks i n the to  interaction  accretion.  ii  between  the  thesis  Stikinia and  the  Table of Contents INTRODUCTION  1  1.1  INTRODUCTORY  STATEMENT  1  1.2  LOCATION A N D METHODS  1  1.3  PREVIOUS  4  1.4  G E O L O G I C A L SETTING  WORK  7  STRATIGRAPHY  13  2.1  GENERAL AREA  GEOLOGY  2.2  T H E SPATSIZI G R O U P  17  2.2.1  The  Joan Formation:  27  2.2.2  The  Eaglenest Formation:  29  2.2.3  The  Gladys  Formation:  32  2.2.4  The  Groves Formation:  33  2.2.5  The  Walker Formation:  34  2.3  FACIES  2.4  UNCONFORMITIES  2.5  DEPOSITIONAL  AND  STRATIGRAPHY  OF  THE  SPATSIZI  CHANGES A N D DIACHRONISM  13  35 37  HISTORY  OF  THE  SPATSIZI G R O U P  39  2.5.1  Interpretation: The  Joan Formation  39  2.5.2  Interpretation: The  Eaglenest Formation  40  2.5.3  Interpretation: The  Gladys  45  2.5.4  Interpretation: The  Groves and  STRUCTURAL  Formation Walker Formations  46  GEOLOGY  48  3.1  FOLDS  48  3.2  FAULTS  51  3.3  DISCUSSION  53  BIOCHRONOLOGY 4.1  INTRODUCTION;  54 ZONAL  SCHEMES  PROVINCIALITY  AND  AMMONITE 54  iii  5.  6.  4.2  ZONATION OF NORTH AMERICAN FAUNAS  55  4.3  Z O N A T I O N O F T H E SPATSIZI F A U N A  56  4.4  THE PLIENSBACHIAN/TOARCIAN BOUNDARY  59  PALEOBIOGEOGRAPHY  60  5.1  A M M O N I T E PROVINCIALITY  5.2  PROVINCIALITY FAUNA  5.3  O L D TO NEW WORLD  SYSTEMATIC  IN  IN THE O L D WORLD  WESTERN  NORTH  60  AMERICA;  THE  SPATSIZI  MIGRATION ROUTES  68  PALEONTOLOGY  6.1  INTRODUCTION  6.2  MEASUREMENTS  76 76  A N D ABREVIATIONS  76  6.3 S Y S T E M A T I C D E S C R I P T I O N S Superfamily E O D E R O C E R A T A C E A E S P A T H , 1929 Family P O L Y M O R P H I T I D A E H A U G , 1887 Subfamily P O L Y M O R P f f l T E N A E H A U G . 1887 Genus Uptonia B U C K M A N , 1897 Uptonia  63  77 77 77 77 77  sp  78  Genus Dayiceras S P A T H , 1920 Dayiceras sp Subfamily A C A N T H O P L E U R O C E R A T I N A E A R K E L L , 1950 Genus Acanthopleuroceras H Y A T T , 1900 Acanthopleuroceras  Genus Tropidoceras  cf.  Tropidoceras  sp  Luningiceras  pinnaforme  Genus Luningiceras  A. stahli  H Y A T T , 1867 SMITH,  (OPPEL,  Family E O D E R O C E R A T I D A E S P A T H , 1929 Genus Metaderoceras S P A T H , 1925  Genus Dubariceras  DOMMERGUES,  freboldi  Family C O E L O C E R A T I D A E Genus Reynesocoeloceras Reynesocoeloceras  1981  87  MOUTERDE  H A U G , 1910 G E C Z Y , 1976 R. incertum  (FUCINI,  Family D A C T Y L I O C E R A T T D A E H Y A T T , 1867 Genus Aveyroniceras P I N N A and L E V I - S E T T I , Aveyroniceras Aveyroniceras  86  sp. sp.  and R I V A S ,  D O M M E R G U E S et al., 1984  cf.  A B  Ammonite gen. et sp. indet Superfamily P S I L O C E R A T A C E A E H Y A T T , 1867 iv  82  84  muticum ( D O R B I G N Y , 1844) aff. M. muticum evolutum ( F U C I N I , 1921) cf. M. mouterdi ( F R E B O L D , 1970) silviesi ( H E R T L E I N , 1925) sp  Metaderoceras Metaderoceras Metaderoceras Metaderoceras Metaderoceras Metaderoceras Dubariceras  1853)  85  1981  SMITH,  79 80 ...81 81  1905)  1971  88 88  1984  90 .92 94 96 100 102  103  104  108 108 Ill  112 112 113 115  116 119  Family O X Y N O T I C E R A T I D A E Genus  Fanninoceras Fanninoceras  HYATT,  McLEARN,  Fanninoceras  1875  McLEARN,  latum sp  119  1930  119  1930  119 121  Superfamily H A R P O C E R A T A C E A E N E U M A Y E R , 1875 Family H E L D O C E R A T I D A E H Y A T T , 1867 Subfamily A R I E T I C E R A T I N A E H O W A R T H , 1955 Genus  BUCKMAN,  Leptaleoceras cf.  Leptaleoceras  Genus  Arieticeras Arieticeras  propinquum sp. A sp. B  Genus Protogrammoceras Protogrammoceras  7.  SUMMARY  N E U M A Y R , 1875  SPATH,  Lioceratoides  Lioceratoides Lioceratiodes Lioceratoides  1862  1868)  1919  (WHITEAVES,  SPATH,  paltum  122  (REYNES,  algovianum ( R E Y N E S , 1868) cf. A. ruthenense (REYNES,  Subfamily H A R P O C E R A T I N A E Genus  1918  L. pseudoradians  OPPEL,  Arieticeras  122 122 122  A N D CONCLUSIONS  123  126 127 130  132 132  1884)  1913  BUCKMAN,  1868)  134 137 138  139 1922  140  144  BIBLIOGRAPHY  147  APPENDIX  1  157  APPENDIX  2  183  v  List of Figures and Plates  Figure  Page  1.1  Location M a p  3  1.2  Geological M a p of the Thesis  1.3  Location map; Previous work  5  1.4  Terrane  8  1.5  Regional geology, north-central  2.1  Triassic/Jurassic  2.2  Diagramatic cross-section,  2.3  Lithostratigraphy, Section  2.4  Pliensbachian lithostratigraphy and biostratigraphy, Section  2.5  Lithostratigraphy, Section  2.6  Pliensbachian lithostratigraphy and biostratigraphy, Section 2  22  2.7  Lithostratigraphy, Section  3  23  2.8  Lithostratigraphy, Section  4  24  2.9  Pliensbachian lithostratigraphy and biostratigraphy, Section 4  25  2.10 Pliensbachian lithostratigraphy and biostratigraphy, Plateau Section  26  3.1  General structure, Spatsizi area  49  3.2  Cross-sections,  3.3  Comparitive stereoplots;  4.1  Pliensbachian range chart of the Spatsizi fauna  57  5.1  Liassic faunal realms in Europe  62  map, Intermontane  Area  mzrpoeket  belt British Columbia  10  geology, Spatsizi area  14  Spatsizi area  15  1  19 1  20  2  21  thesis map area  is==pe^k|tll^-^'^  thesis map area vs Groundhog coal  field  52  5.2a Position of major Cordilleran terranes during the Pliensbachian  66  5.2b Present position of Cordilleran terranes  67  5.3  Early Jurassic paleogeography  71  6.1  Graph comparing Eoderoceratidae  rib  6.2  Graph  rib  comparing  and faunal migration routes  density density  between between  certain  members  Leptaleoceras  pseudoradians  the  family 99 and  L. 125  accuratum  AP.lParameters and parameter  of  groupings of computer vi  data  „  ..158  Plate 1 Uptonia  sp.;  sp  Dayiceras  191  Plate 2 Dayiceras  sp.;  cf.  Acanthopleuroceras  193  A. stahli  Plate 3 Luningiceras  pinnaforme;  Tropidoceras  sp.;  Metaderoceras  195  muticum  Plate 4 Metaderoceras  197  muticum  Plate 5 Metaderoceras  aff.  M.  cf.  M.  muticum;  M.  cf.  M.  199  mouterdi  Plate 6 Metaderoceras  mouterdi;  Ammonite gen. et sp. indeL  Metaderoceras  sp.;  M.  evolutum;  M.  silviesi;  201  Plate 7 Metaderoceras  silviesi;  Dubariceras  203  freboldi  Plate 8 Dubariceras Aveyroniceras  freboldi; sp. B  cf.  Reynesocoeloceras  R.  incertum;  Aveyroniceras  sp.  A.; 205  Plate 9 Fanninoceras latum; Arieticeras algovianum  sp.;  Fanninoceras  Leptaleoceras  cf.  L.  pseudoradians; 207  Plate 10 Arieticeras  Plate  cf.  A. ruthenense;  Lioceratoides  propinquum  sp.  Protogrammoceras  209  11 Lioceratoides  sp.  A;  Lioceratoides  B;  vii  paltum  211  ACKNOWT .FDGFMFNTS The  realization  of  this  thesis  generosity,  a n d : sense  of  humour  importance  to ithe  accomplishment  of  is  due, i n large  my thesis  o f this  work  part,  advisoT,  to the valuable  D r . P.  L.  was the constructive  Smith.  guidance, Of  "Devil's  advocacy"  provided by D r . ' H . W. Tipper o f the Geological Survey o f Canada. M y sincerest go to both o f ithese people for their confidence This study was supported by grants Engineering  Reasearch  Council  equal  thanks  and encouragement  to P. L . Smith from the Natural Science and  and Chevron Canada  Limited.  The Cordilleran Section  of  the Geological Survey of Canada is gratefully acknowledged for logistical support while in the  field,  and for provision of work and storage space for the fossil collections  this study. Thanks uncanny  go to M . Akehurst, head  ability, to procure the obscurest  her patience Parts  with one so neglegent of this thesis  librarian of the Geological  of journals in the shortest  Survey,  used in for her  possible time, and for  of library due dates.  were critically reviewed by Drs. W.  C . Barnes,  R. M . Bustin,  and J. V . Ross. T h e i r help is greatiy appreciated, as are the many useful discussions ;  I. W.  M o f f a t on the structure  helped untangle The  and stratigraphy  during the textforming of this work.  of G . Hodge and the photographic services  invaluable to the illustration of this The  of the Spatsizi region. J. R. Montgomery  many computer problems encountered  drafting services  moral support needed  with  of E . Montgomery were  thesis. to complete  parents and by E. Gauthier.  viii  this thesis  was abundantly supplied by my  1.  1.1  INTRODUCTORY The  STATEMENT  Stikine  comparatively  little  INTRODUCTION  River study  region  because  of of  north-central  its  isolated  British  location,  Columbia  rugged  terrain,  has  received  and  complex  stratigraphy and structure. Recent work i n the area (Tipper and Richards, 1976; al,  1984)  has shown that paleontology, and i n particular ammonite  Smith  et  biostratigraphy, can  be  useful in unravelling the lithostratigraphy of the area. Previously undivided rock units have now been subdivided and correlated with other units of markedly different  facies.  The objects of the present study are: 1)  to  describe  and illustrate  the  determine their stratigraphic 2)  to  describe  the  Pliensbachian  ammonites  from the  study area  and  to  range;  Pliensbachian  to  Bajocian  lithostratigraphy  and  to  map  the  distribution and structure of the rock units within the study area; 3)  to analyze  the  facies relationships based  on b i o -  and lithostratigraphic data  and  to  relate these data to a regional geologic framework; and 4)  to describe theories  the paleobiogeographic  implications of the  concerning ammonite provinciality and the  fauna i n view of  tectonic  contemporary  evolution of the  Western  Cordillera.  1.2  LOCATION The  A N D METHODS  study area  is in the  Spatsizi Plateau Wilderness Park in north-central  British  Columbia. Detailed field mapping and most of the fossil collecting were carried out i n an area  roughly 80  confluence and  1.2,  of the  square  kilometres in the Eaglenest  Stikine and  Klappan Rivers ( N T S  in map pouch). Field work was conducted  Range, map  about area  65 k m southeast of 104  H  (Spatsizi),  from June to August, 1983,  fig.  1.1  from a  helicopter supported camp near a small unnamed alpine lake near the centre of the  1  the  thesis  2  area (fig.  1.1).  Fossils were the  thesis  area.  (Compton, from  The  1962).  localities  collected  sections  Fossils  less  In were 1,  made  50  measured  recorded  in  distant  were  m  131-134, the  ascending  the  Brunton  stratigraphic  tied into the  localities in  and  tape  technique  order,  and  collections  sections  where  possible.  True  data using the Fortran IV programme S T R A T (Smith, 1976). the  collections  from  from localities outside the  measured,  using  and from scattered  and the position of the fossil collections within the sequences were  addition to  localities  not  field  were  were  than  stratigraphic thicknesses calculated from  from four measured sections  138,  and  relative  142;  the  thesis see  stratigraphic  thesis  map  area,  three  fossil  area but within the Eaglenest  also  appendix 2).  position  of  the  Although  fossils  Range  these  within  collections (figure  sections  each  were  section  was  recorded. In  this  ammonites,  as  study, well  both as  quantitative  stratigraphic  and  and  qualitative  systematic  morphologic  data  have  been  pre-existing ammonite data base. This data base, managed by T A X I R of  the  University  of  British  Columbia's  computer  data  database was initiated by D r . P . L . Smith to facilitate the Jurassic this  ammonite  data  can  computer's database that  has  Lower  data from North  quickly  statistical  are  Jurassic  demonstrate  entered.  It  is  be  The  Appendix 1, hoped  entered  statistically  along with that  systems.  The  paleontologic and biostratigraphic problems  its potential for more widespread use.  that  this  Once  by  interfacing  can  be  computer print-outs of  application of  the  into  a  ammonite  storage and retrieval of Lower  examined  various parameters  of  (Brill, 1983), is one  America and Europe (Smith, in press).  easily  programmes.  listed in  been  and  base  characters  ongoing  in western  entered the  with  the  into  Spatsizi  computer North  entered,  the data  work  to  America will  FIGURE  1.1  Location map.  4  1.3  PREVIOUS W O R K The  scattered.  First references to Lower Jurassic  K e r r (1948) reported  Creek area (fig. 1.3)  based  the  on  occurrence  they  included in  i n north-central Lower Jurassic  British Columbia are  rocks  in the  Telegraph  from an unnamed group of volcanic and  of the thesis area, in the Hazelton and Smithers map  areas, Armstrong (1944a, b) and Kindle which  of  fossils collected  sedimentary rocks. T o the southeast  rocks  rocks  the  (1954) reported the  lowermost  unit  of  the  occurrence  of Lower  Hazelton Group.  Jurassic  Lord  (1948)  defined the upper division of the Takla Group i n the McConnell Creek area as being Early  to middle Late  Jurassic  Triassic, and therefore  age.  at least  Current usage  part of the  restricts  the  upper division  Takla Group to the  of  Late  of Lord's Takla G r o u p would  now be considered as Hazelton Group. "Operation Canada,  in  Stikine"  1956,  was  the  carried out the  northern part of the  code-name  first  under  regional  Bowser Basin and other  which  geologic  map  the  Geological  study of  areas to the  an  area  Survey  including  north (fig. 1.3).  In  of the the  following year a 1:250,000 map with accompanying descriptive notes was published (G.S.C., 1957). Reference although  not  to the  formally  Lower Jurassic named,  the  rocks of the  nature  and  area  extent  was made  of  the  in this report,  Bowser  Basin  and  was  first  commented upon. In  1966,  Souther  synthesis of north-central the  large  Armstrong  sedimentary (1966)  and Armstrong published a British Columbia and  basin  delineated  constructed  a  by  Lower  first  comprehensive  applied the name  Operation Stikine Jurassic  geologic  paleogeographic  of  Spatsizi  illustrating  the  relations  between  volcanic,  tectonic  "Bowser Basin"  (G.S.C., 1957). map  northwest portion of the province and from this made a cross-section south  and  Souther  for  the  and entire  of the area to  sedimentary  and  to  the  basement  ' rocks. Systematic Jurassic  mapping by  the  rocks and fossils of the  G . S . C . , and the  detailed documentation  of  the  Lower  Spatsizi and surrounding map areas did not begin until  5  132 W 59*N #  58*N  REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.  FIGURE  1.3  1948, Kerr (Telegraph Creek) 1944a,b, Armstrong (Hazelton, Smithers) 1948, Lord (McConnell Creek) 1954, Kindle (Hazelton, McConnell Creek) Operation Stikine (G.S.C.) 1972, Souther (Telegraph Creek) 1972, Carter (Toodoggone) 1974, 1980, Richards (Hazelton) 1976, Richards (McConnell Creek) 1976, Tipper & Richards 1977, Gabrielse et al. (Toodoggone) 1978, Tipper (Cry Lake) 1978, Monger & Thorstad (Cry Lake, Spatsizi) 1978-1980, Anderson (Hotiluh Batholith) 1979, Gabrielse (Cry Lake) 1980, Gabrielse (Dease Lake) 1984, Smith et al. (Spatsizi)  Map of  illustrating the location o f previous studies the S p a i s i / j and s u r r o u n d i n g N T S m a p areas.  54* N 126"W  on  the Lower Jurassic  6  the  1960's.  Jurassic the  the  (1964,  ammonoid faunas  ages of  Columbia (104  Frebold  G)  rock  were  1970)  the  only  units published i n subsequent  determined  Creek  based  area  on Frebold's  geologic work. In  1972). Lower Jurassic  demonstrated  the  presence  Sinemurian), Upper Pliensbachian and Upper Toarcian In  1974  (Richards,  1974),  sedimentary area the  (94  an  open  file  showing  map  the  rocks. Just to the  D ) , abundant  volcanics  detailed  systematics  on  the  Early  of northern British Columbia and southern Y u k o n , and most  was published (Souther,  Telegraph  published  of  the  north of the  of  i n the  the  ammonites  Telegraph and  map  area  British  Creek  bivalves  (now  (93  to  map  found i n  thought  sediments  M)  was  Bajocian  to  be  published  volcanic  and  M c C o n n e l l Creek  map  and volcanics, correlative  with  Hazelton area, in the  Hazelton area,  north-central  of Hettangian  Sinemurian  Lower to Middle Jurassic  and sediments  1972,  on  sediments.  Hazelton  distribution  reports  of  yielded a rich Sinemurian to  Bajocian  fauna (Tipper, 1976). The  Lower . and Middle  Jurassic  fauna  and stratigraphy  and McConnell Creek map areas was documented the most comprehensive north-central  summary of the  development  reader  Smithers, Hazelton,  by Tipper and Richards (1976). This is  publication on the Jurassic  British Columbia. The  of the  fauna and stratigraphy for any part  is also referred  to this paper  of the  Mesozoic stratigraphic  nomenclature  extensive  volcanic pile in the  Toodoggone  for an for  of  excellent  north-central  British Columbia. A  thick  east of the  and areally  thesis  area,  was  mapped  as  Lower Jurassic  Gabrielse et al. (1977) as Lower to Upper Jurassic. as  the  Toodoggone  volcanics,  mark  been dated isotopically (Gabrielse Pliensbachian  to  Bajocian.  the  northern  et al., 1980)  Toodoggone  thesis area i n the core of an anticline.  volcanics  by  Carter  map area  (1972) and  (94  E),  later  by  These volcanics, informally referred  margin of the  Bowser  Basin  and  have  and paleontologically (Smith et al., 1984) of  Pliensbachian  age  are  exposed  in  to  as the  7  To the north of the Spatsizi map area, (1978) and Gabrielse the  Pliensbachian  sediments.  West  (1979) report  Takwahoni of  the  Gabrielse (1980) reports Recent time  detailed  the thesis area, Jurassic the  time.  Stikine  surrounding  sediments  by Anderson  through  i n the Dease  Bajocian  Lake  a fundamental  in the Spatsizi area.  1980)  on the  bodies  form  on the Lower  and  (104  J),  Formations. distribution and located  during Late Triassic  igneous  control  north  of  and Early  the backbone  of  Jurassic volcanic and  area. rocks  have  It was not until  discovered  emplaced  and related  Jurassic  the thesis area.  1979,  volcanics  map area  o f the Hotailuh Batholith,  that the intrusions were  Lower  were  Toarcian  (1978,  o f the various phases  and exerted  ammonites,  and  Inklin Formation,  further occurrences o f the Inklin and Takwahoni  The Hotailuh Batholith  summary,  o f the Upper Sinemurian  map area,  stratigraphy i n the Spatsizi  In  with  C r y Lake  indicate  Arch  sedimentary  sediments  Formation,  studies  of emplacement  i n the C r y Lake map area (104 I) Tipper  below  been  found  i n almost  all  the  1981 that Lower Jurassic sediments,  Middle  to  Upper  Jurassic  Bowser  The aim o f this thesis is to document,  the Pliensbachian and Toarcian elements of this  areas replete  Lake  Group  for the first time,  fauna.  1.4 G E O L O G I C A L S E T T I N G The  Canadian Cordillera can be divided into five physiographically and geologically  distinct belts that are parallel to the northwest-southeast Three  of these  belts,  low-grade metamorphic Intermontane, Plutonic deformed,  the  and  high-grade  Intermontane,  or unmetamorphosed  and Rocky  Complex  Insular,  Mountain Belts by  the  metamorphic  Monger et al. (1982) as major  Omineca  rocks  tectonic  and Rocky  Mountain  Belts  consist  of  of varying structural style. The Insular,  are separated Crystalline  and plutonic  grain of the Cordillera (fig. 1.4).  rocks,  from Belt  one another which  and  have  welts within the Cordillera.  consist been  by the of  Coast  intensely  described  by  8  *  t*  / 80  L  -i  s  '-A  *.  • IV 0  (a)  (b) // - Coast Plutonic Belt  IV - Ominica Crystalline Belt V - Rocky Mountain Belt  FIGURE  1.4  200  300  Kilometres  49 N  I - Insular Belt  /// - Intermontane Belt  100  1  Stikine Terrane MW%  ?  Cache Creek Terrane Quesnel Terrane  W///A Bowser Basin <i/////.  L o c a t i o n o f the Intermontane belt w i t h i n the C a n a d i a n C o r d i l l e r a (Tig. 1.4a) a n d the p o s i u o n o f the t e c t o n o - s t r a t i g r a p h i c terranes c o m p r i s i n g the Intermontane bell (Tig. 1.4b; m o d i f i e d f r o m T i p p e r et al., . 1 9 8 1 ) .  9  The distinct  crustal  consistent and  Insular  and  fragments  or  or  zones  history of the  to,  with,  interaction  described by Coney terrane  Stikine  terrane,  of  Mesozoic  Intermontane terrane which  or the  eugeocline  of  volcanic rocks. The terrane,  differs  are  often  amalgamation  of  terranes  marked by  continental  by  geologically  an  internally  surrounding  are  separated  plutons  of these terranes  American  smaller,  characterized  from those  setting. The  which  North  is  of  or  by  is  major  covered  and of their  margin  terranes  on  the  distribution of  Early  Jurassic  accretion  complex  ammonites  is  is  not  Belt  includes parts  Stikinia, Quesnellia, thesis the  Bowser  area  is  a  of three  major  and  Cache  part,  Basin, a  technically part  of  major  the  the  was  Canadian Cordillera  formed  and  geologic  Stikine  basin during the Middle and Late Jurassic  and  is  effects,  discussed  tectono-stratigraphic  in  Creek in  consists feature  terrane  the  Late  mainly of  The  sedimentary  formed as  post-dates  Stikine  Paleozoic-Early  superimposed on  because it  and therefore  terrane.  terranes;  the  the a  and  Upper Jurassic,  and their  present  day  and  Stikine successor  eugeoclinal origin  of Stikinia. Sediments of the Bowser Lake G r o u p were deposited in the basin during Middle  by  (paleobiogeography).  The the  that  composed  et al. (1980), Monger et al. (1982), and Monger (1984). The  displacement  chapter 5  the  both  terrane  of a particular tectonic  younger rocks. The  of  are  Each  assemblage  structurally complex  and  Belts  terranes.  tectono-stratigraphic  is characteristic  faults  Intermontane  distribution delineates  the  basin  the (fig.  1.5). The Group  Lower Jurassic  sediments  in  an  formation of the thesis  rocks analyzed i n this study are  erosional/structural rocks, and to the  window.  The  subsequent  exposed  geologic  below Bowser  events  formation of the  leading  Lake  to  the  Bowser Basin  are  outlined i n the following discussion. During activity. Stuhini  In  the  the  volcanics  Late Triassic, the  Stikine were  River  region  deposited  and  Stikine terrane of  the  formed  was the  Stikine the  site  terrane,  basement  to  of considerable  the  Triassic,  subsequent  volcanic  calc-alkaline  volcanism and  10  LEGEND Middle to Upper Jurassic Bowser Lake Group sediments  •ao*  Late Triassic-Early Jurassic plutonic rocks V VV V  YYYY •  -< \\  7*/  ,~-~{  •>/.'- *>->'~'  ^  THESIS MAP AREA  4 1.5  o  K  o  ' V  V  V  ty  100  Kilometres  Cache Creek terrane Mississippian-Triassic  •  x' -'>  50  Late Triassic volcanics (Stuhini facies)  Hotailuh Batholith-  v - >' -  •-i'-'-'0?/r.;  FIGURE  EH  J"A\_*TV  - >, i ' i  -  A A A A A A A A  Early Jurassic volcanics (Hazelton & Toodoggone)  V  ^ / \ A A A A  V '  v v v  N  A A A , A A / O A ,  / v v C^" v v  54'  ( V  V  '  |t\V v v l  Topley  Intrusions  Geological map o f the n o r t h - c e n t r a l British Columbia outlining the d i s t r i b u t i o n o f major Triassic a n d Jurassic rock groups, tectonic features and t e n a n e boundaries ( m o d i f i e d f r o m T i p p e r et al., 1981).  11  sedimentation  i n the Stikine River and Hazelton regions. The Stikine A r c h  also began  to  rise during the Late Triassic (Anderson, 1978, 1980; Tipper and Richards, 1976). Some of the  intrusions  that  volcanics (Souther, At Creek and  the  terrane, Omineca  along  the  make  are  thought  to be  comagmatic  with  the Stuhini  1976).  close  of the  located  along  Crystalline  Stikine  up the arch  Arch  Late  Triassic  and possibly  the northwest-southeast  Belts,  also  and the  began  Cache  to  rise  Creek  the  earliest  boundary (Tipper  terrane  Jurassic,  between  the  and Richards,  resulted  i n the  the  Cache  Intermontane 1976).  division  Uplift of the  Triassic eugeocline into distinct basins;  the dominantly volcanogenic Hazelton Trough to the  west  Whitehorse  and southwest,  Trough  the sedimentary  to the east  The Hazelton Trough extended  to the Chilcotin area i n southwestern Yalakom volcanism  Trough  to the north,  from the Stikine A r c h  British Columbia where  formed  the rocks  of the  Hazelton Group  Quesnel  i n the north  it is now truncated  fault This was the site of all Lower to early Middle Jurassic which  and the  by the  sedimentation and  of southwestern  and central  British Columbia. The Hazelton Trough was also the locus o f deposition of the sediments and volcanics, analyzed in this study, that are distributed along the southern  flank of the  Stikine Arch. Although these northern Hazelton Trough rocks are coeval with the Hazelton Group  farther  to the south, they  are considered  to be of different  origin and  therefore  not strictly equivalent to the Hazelton G r o u p for the following reasons: 1)  the two rock  units, although partly time  equivalent,  are geographically  separate from  one another; and 2)  the volcanics (Souther,  i n the northern  1977), whereas  core of the ancestral  part  of  the  trough  are related  Skeena  volcanics and sediments  Arch  the Hazelton volcanics are genetically related to the plutonic Arch (Tipper and Richards, 1976).  In view of the foregoing, and following the precedent the  to the Stikine  set by Smith et al. (1984),  deposited i n the Stikine River region of the Hazelton Trough  are referred to i n this study as the Toodoggone  volcanics and Spatsizi G r o u p , respectively.  12  Volcanism Bajocian  time  intrusions, Bowser the end  and related  when  was  the  uplifted,  Basin to the  northeasterly dividing  eugeoclinal  sedimentation  the  north and the  Skeena Arch, manifested to  sedimentation  conditions  in the resultant  i n the in  continued  trending Hazelton  Nechako  in the  Skeena Trough  Basin  Hazelton Trough until  Arch, into  to the  Hazelton  successor basins.  Trough,  and  by  successor  south. The  Stikine region by a major the  two  cored  the  Early Topley  basins,  Bajocian  uplift of  volcanic pulse, marked the  beginning  of  the  the  molasse  2.  2.1  GENERAL GEOLOGY The  part  of  STRATIGRAPHY  A N D STRATIGRAPHY  O F T H E SPATSTZT A R E A  Lower Pliensbachian to Lower Bajocian  a  complex  package  of  early  Mesozoic  sediments  examined  plutonic, volcanic,  in this study  and  sedimentary  are rocks  that crop out along the southern flank of the Stikine A r c h . Informal designation of these sediments  as  the  Spatsizi  Group,  the  relationship  between  and  the  and their depositional history  are  The distribution of Triassic and Jurassic rocks in the Spatsizi area is shown i n  fig.  volcanic rocks of the area, the nature of the sediments, discussed in this  and a diagramatic  fig.  2.2. Triassic volcanics of the as  mentioned  volcanic  and  Arch,  Triassic  cross-section  in  the  sedimentary  Sinemurian age Stikine  have in  Group  illustrating their stratigraphic relationships is shown i n  Stuhini Group are  preceeding  rock  units  chapter, in  the  Cry  of  the  Spatsizi i n the  McConnell  and  of  the  Lake  map  Sinwa  form  the  Sinemurian (Tipper,  (Hazelton  age  well  to  Rocks  of  1978).  rest  Also,  map  to  in the  all  subsequent  are  and  north of  the  unconformably  on  the  southeast  areas, Sinemurian  Group)  area  Hettangian  although to the  sediments  Hazelton, and Smithers Formation  basement  area.  Spatsizi area,  Formation  Creek,  Telkwa  area,  the oldest rocks exposed  Spatsizi  not been found in the  the  limestones  sediments  Spatsizi  chapter.  2.1  and,  the  abundant  of  volcanics  (Tipper  and  Richards, 1976). Rocks  of  Pliensbachian  are  distribution is discontinuous. Extensive volcanics from  are  the  Spatsizi  Stikine Group  sedimentary basinward  exposed  Arch (fig.  rocks into  along the  is  these  2.2). not  sediments,  volcanics nature  clearly or  Pliensbachian  southern  The  if  the  represented  replaced  of  the  understood. volcanics  13  Stikine by  Whether  Arch  although  transition  the  abruptly is  volcanics not  Southward  sediments from thin  known,  their  Toodoggone  (fig. 2.1).  Pliensbachian  southward  end  Spatsizi,  flows and breccias of the  flank of the are  in  of  the  volcanic and however,  to  grade the  0 o 10 o TOODOGGONE  SPATSIZI  VOLCANICS  • •  GROUP  ao'ji T h e s i s m a p - (J>C area 4 x  *tofe  PUenabachian  •  •  Toarcian Pliensbachian  Northern limit of Bowser Lake Group. sediments  Lower Jurassic plutona  FIGURE 2.1  Geological map of the upper Stikine region showing the distribution of the Toodoggone volcanics and their basinward sedimentary equivalents of the Spatsizi Group (modified from Gabrielse and Tipper, 1984, and Smith et al., 1984).  SE  NW STIKINE  ARCH  SECTION Z  B a i o c i a n •  " \ A - - •  • ,  SECTION Y  SECTION  THESIS MAP AREA  X  Lower Bajocian  A ,\ .rrrT. A  , A  A  ' A A A A A-S-  A  ^  fa^  AaTenian Upper Middle Lower  —i  o  01  o 01 3  Upper Pliensbachian Lower Pliensbachian  • - - t f c T ^ ^ T r ia s 8 i c  F I G U R E 2.2  ) ^  v  ^ ^ ^ ^ ^ ^  Diagramatic cross-section showing the inferred stratigraphic relationships of the Toodoggone volcanics and the Spatsizi Group sediments along the southern margin of the Stikine Arch. Note that the time scale on the right applies only to rocks of the Spatsizi Group and Toodoggone volcanics and not to the underlying Stuhini and Hotailuh rocks.  16  transition  probably  sedimentary on  represents  basin  environment  the  southern  flank  Rather,  Toarcian  volcanics  intrusions  of  Anderson,  a  the  1980).  of  facies  (Smith  the  North  minor  the  but  sediments  Batholith  of  Arch  from  (Smith  Stikine  a  volcanic  arc  1984). Pliensbachian  et al.,  Stikine  and  Hotailuh  change  are lie  volcanics  present  directly on  et al..  Arch,  not  1984;  environment  on  top  of  and  sediments  the  arch.  and on  Perry,  of  a  abundant  Stuhini volcanics  Henderson  Pliensbachian  are  to  the  1981; Laberge  G r o u p (Takwahoni facies) are present i n the C r y Lake area (Tipper, 1978). The the  distribution of  Pliensbachian  unconformably with  the  on  rocks.  Toarcian As  Triassic  Pliensbachian  in the  mentioned,  rocks  on  volcanics,  southward) by sediments  rocks  Toarcian  the  the  Spatsizi  area  volcanics  is  more  and  minor  upper  flanks and  top  of  the  Toarcian  volcanics  are  replaced  continuous  than  sediments  rest  Stikine  Arch.  basinward  (i.e.,  of the Spatsizi Group.  Early Bajocian rocks of the Spatsizi area have a similar distribution pattern as Pliensbachian of the be  noted that  Walker than the  the  Formation  either  the  rocks;  of the  give way to sediments Bajocian  described  sediments  Upper Jurassic  during  the  extent of  sediments  the  continue  become shalier and their of the  of the  flank  Spatsizi Group (i.e., rocks belonging to 2.2)  have  a greater volcanogenic  The  Bajocian  the  component  indicating a difference in  centre(s) of volcanism, or a change  Bajocian.  southern  sediments  are  the  unconformably overlain by clastic sediments  in the  general  youngest of the  rocks Middle  Bowser Lake Group.  cover of the overlying Bowser Spatsizi  outcropping along the  the  of the Spatsizi G r o u p to the south. It should  below i n section  Spatsizi G r o u p and are  total  volcanics  Toarcian or the Pliensbachian sediments, perhaps  environment  The  the  Bajocian  type of volcanism, a shift i n the  tectonic  and  and Toarcian  Stikine Arch  As  Spatsizi G r o u p is  unknown due  Lake G r o u p south of the for  a  volcanogenic  basin of deposition as implied  considerable  to  the  almost  unbroken  Stikine A r c h . It is assumed  distance  below  this  cover  where  component  diminishes southward towards the  by  et al. (1984), and Tipper and  Smith  that they  centre  Richards  17  (1976) for the Hazelton Group.  2.2 T H E SPATSIZI The  GROUP  area underlain by the Pliensbachian  to Lower Bajocian  this study was, prior to the first close examination  sediments  examined i n  i n 1981 by the Geological Survey of  Canada, thought to have been underlain by M i d d l e to Upper Jurassic Bowser sediments.  Since  recognized  as comprising a distinct lithostratigraphic  this  as the Spatsizi  study  1981, however,  Group and its component The Park shown  name  one of which or type  to  formations (described  Lower  outcrop.  stratigraphic (section  section.  1,  intention  to formalize  figs.  areal  extent  formations Eaglenest  2.3  and 2.4)  is here  of an incomplete  Formations  Wilderness  designated  section  Group is  as  the  examined  (figs. group  about  10  X , fig. 1.1) is given in fig. 2.10. In the thesis  is marked by a disconformable  contact with underlying  volcanics, and the upper boundary is defined by a slight ( < 5 ° ) Lake Group. of up to 900  i n the field and mapped at a scale of 1:25000 (fig. 1.2). These  are described Formations  to i n  measured  Five formations of the Spatsizi Group, together attaining a thickness delineated  been  the Spatsizi  of the Spatsizi  angular unconformity with the overlying Ashman Formation of the Bowser  m, were  have  the Spatsizi Plateau  sections of the Spatsizi Group were  km north o f the thesis map area (Section  flows of the Toodoggone  rocks  below) i n forthcoming publications.  The total  The description  map area the base o f the section  Bajocian  unit that is informally referred  of the Spatsizi G r o u p is derived from  i n fig. 2.1. Four  stratotype,  Pliensbachian  Group. It is the author's  i n which the sediments  2.3-2.9),  the  Lake Group  below  were  i n ascending  studied  stratigraphic  i n greater  detail  order.  than  Note  Gladys,  due to the sparsity o f fossils (particularly ammonites)  five  that the Joan and Groves,  and Walker  i n the latter three units.  LEGEND FOR FIGURES 2.3-2.10 Tuffaceous shale  S i l t s t o n e s and fine s a n d s t o n e s  Shale  Limestone  Siltstone  Conglomerate I U  Ul  ^ A i A A k A i  Volcanic flows and b r e c c i a s  ( S e e l e g e n d of figure 1.2 o  e  f o r d e s c r i p t i o n of  Formations  F o s s i l l o c a l i t i e s ( e x s i t u , in s i t u ) Conformable contact (defined, assumed) Unconformable contact (defined, a s s u m e d )  See  figure  1.2  f o r l o c a t i o n of s e c t i o n s  and figure  1.1  f o r l o c a t i o n of s e c t i o n  1-4, X.  FOSS1  STRATIGRAPHY :  LOCALITES 3  «  9  09  Unit, stage, contact relationships  X  CD  BOWSER GROUP  LAKE  Ashman Formation  900------: 09  e . «*  3" 3  P  05  3  800  SPATSIZI GROUP  700-  AAA AAA AA AA AA A AA AA A A AA £A A AA AA  54  a  Walker Fm.  a  a  a  a a  1 a  A  A  a  A  a  A  rjs to o' o  a  a  a  A  A A A A A , A A A  A  A  A  A  A  A  to  A A A  3  600 &  A  A  A  A  A A  A  A  A A A  A  A A  53  a  -~-~-"\  52  500-  Groves Fm. Aalenian Gladys Fm.  o.G  0)  <B  £ w  CO UJ  3 •O  400-t  m7  z  o  I  48  68 45,46 49.67 42 40.41  47 Eaglenest Fm. 44 43 37 38,39  H  o 2 o ~  «* Q.  o  300-  a  ST 3*  34,35  3  i  33 32  o r  sr s  200  31  30  100  Upper Pliensbachian Joan Fm. Lower Pliensbachian F V'V'V V V V VI (7 V V V , V V V VI > V V V V 7  TOODOGGONE VOLCANICS  T  FIGURE 2.3  Section 1, lithostratigraphy  CD  SECTION 1 : Pliensbachtan-Lower Toarcian  •o C  a.  FOSSIL  STRATIGRAPHY: LOCALITIES Unit, stage, CO  CO  CD  SPATSIZI GROUP  CD C CD CO  E E <  X  c  120  contact relationships  co  •*  o  CO  c  CO  o CO  o  110 - E  CD  Eaglenest Fm.  o •  100 - 55  \  o o o o  56  c  .2 JE o CO  J3  -26.27,28  CO  c  CD  CD  a a  3  70-  25  o  24  w  £  23  o  Joan Fm.  60  d)  E  Sz  CO  50  - 22  o i  c  .2 !E o  - 21  CO J O  r~ 4 0 -  CO  20 17  c  18  CD  CD  30-  19 16 15 9 8 7.10 6,11 12  20-  3 2  10-  64  o 13 14 4 5 51 50 63 1  o o  I„v. V V v .  y  TOODOGGONE  v v v i  VOLCANICS  V V V V ^ v V v V  y  7  v ^ V  FIGURE  2.4  J  Section 1, Pliensbachian b i o s t r a t i g r a p h y and l i t h o s t r a t i g r a p h y O  SECTION 2 FOSSIL  STRATIGRAPHY:  LOCALITIES Unit, s t a g e , c o n t a c t => 5 relationships CO  c  X CD  85  500  SPATSIZI GROUP Walker Fm. Bajocian Groves Fm. Aalenian  c  Gladys Fm.  J^cO  3 O  400 Eaglenest Fm. 84  ©  c  CO  •oo ~  CO  2S o  300-  5.1  200-  o co —I o  Upper Pliensbachian  100  •  Joan Fm.  Lower Pliensbachian  v v v  TOODOGGONE VOLCANICS  1  V V V V V V V ' v v V  v  v• FIGURE  2.5  S e c t i o n 2, l i t h o s t r a t i g r a p h y  SECTION 2: Pliensbachian-Lower Toarcian FOSSIL STRATIGRAPHY: L O C A L I T I E S Unit, s t a g e , contact 3 relationships CO CO  co  X  c  SPATSIZI GROUP  1 1 0  £.2 O CO  -J o  Eaglenest Fm. 1 0 0  135  I p..  .2 ic o co x>  90-  o o  CO  83 81  r-  c  82  a> a a  80  3  70Joan Fm. w 60 E CO CO UJ  50 79 78 77  z o  76 75 73  40  80  o  139 c  .2 IE o  74  30-  -  CO  XI  72  05  c  CD  2 0  -  o  10-  71  87  o  70 137 V V V V. V V V \ V V V * V V V S V V V V •v • v v - *• V V J7  FIGURE 2.6  TOODOGGONE VOLCANICS  J  Section 2 P l i e n s b a c h i a n b i o s t r a t i g r a p h y and l i t h o s t r a t i g r a p h y l-o  STRATIGRAPHY:  FOSSIL LOCALITIES  I  2  Unit, stage, contact  relationships  x 4>  BOWSER LAKE GROUP Ashman Formation 900 -T-Z-Z-Z-:  co D «*  O 3 5T  800-^  3  -1  700  SPATSIZI GROUP Walker Fm. . ft ft  a  ft a a a A ft A fi a ft a ftfta < 4 a ft A ft  a  60Q -4  ft  .  ft  4  o  ftftA A ft ft ft fi ft ft ft a a ft ' i ft * * a  a  ft  ft  o  '  A  a a ft * ftftA * ' •k a A a  CD  ft ft ft 6 ft «. , ft ft ft  co  o o 5"  a  500  3  ftftA , ft  ft  ft A ft A ft ft ft  Ai  xn 0)  ftft ftft A A ft A ft ft ftftAA AA ftftftA ftftft  <0  V)  UJ  z  o  A ft AA AA t ft a ft A i a aftA a a A A < A  .  400  I  ft  ft  a  ft  ft ft ft ft ft ft  ftftA A A* aA Aa  90  1  a  ftftftA  r-  A A ft ft A ft - . A -A A A a  Groves Fm  a  Gladys Fm.  -I  o  Oft  c  -o  2.1  to + 3  4  300  •o  Eaglenest Fm.  200  o 2 es ~  89  -» Q.  88  3  no. 5" 5"  100  Lower Pliensbachian  V V v v  ' V V V ,V V V V  r  v v v v v v v v v  FIGURE  2.7  TOODOGGONE VOLCANICS  ' Section3, lithostratigraphy  N  UJ  A SECTION 4 FOSSIL  STRATIGRAPHY:  L O C A L I T I E S Unit, s t a g e , c o n t a c t relationships CO  c  CO X CD  i i  BOWSER LAKE GROUP Ashman Formation  ! I  CD  c  .5 E o CO  CQ  m  e  I  X.  o  SPATSIZI GROUP f  ca  Walker Fm.  a a  CO CO CD  c  __  y  _  Aalenian? -110  co  a_.>  109  200 -  Middle Toarcian  111 Eaglenest Fm.  CD  E'  >^  Lower Toarcian  CO CO LU  z _ 9 -x  100"  Upper Pliensbachian  _____ •  Joan Fm.  Lower Pliensbachian k A A A _ A A A i & A A A A A \ £ A \1 A  TOODOGGONE VOLCANICS  c  FIGURE 2.8  S e c t i o n 4. l i t h o s t r a t i g r a p h y 50  S E C T I O N 4: Pliensbachian-Lower Toarcian FOSSIL LOCALITIES 3 (0  X  c  1 10  STRATIGRAPHY: Unit, s t a g e , contact relationships  CD  0)  SPATSIZI GROUP  -i  c  Is i-  CO  o cc  -j o 100  Eaglenest  - E  90 -  i  ,  1  Fm.  i  107, 136  J.  c  108  CO  o 80-  3  70o % JE  O  106  60  -  105  -  104  Joan  CD  Fm.  co co LU  Z  __ o  X I-  50 c CO  o  40-\  _co CO  c  CD  30-  103  -  102  20-  10-  101  A  100  a  99  covered  V V V V V V V P V V V V. V V V P V V V '  TOODOGGONE  1  VOLCANICS  v v ^ v 'v V  1  FIGURE  2.9  Section 4, Pliensbachian  biostratigraphy and lithostratigraphy  CO c  .2 '•5  SECTION X  CO  3  C  STRATIGRAPHY: LOCALITIES Unit, s t a g e , contact 3. relationships CO  .2  CD _. <  X CD  Eaglenest  cr c  E  CO  w  SPATSIZI GROUP  3 3  a  > 3 o o> ao a bo o  FOSSIL  c  E E  CO CO CO _. CD O O  CL a  c  5.2 Fm.  o  CO  —i o  133  o  E o co  o  134  CO CO LU  c  CO  z _  o  CO J_ CO c  CD  132  LU  aa _3  o  o o  CD  X  T  O rx  Joan  T  Fm.  131  CL 0_ <  o o Lower Pliensbachian r 0  ^ A" A 'A A A A A| A A A A A A A| I- A A A _A A A A M A A : A ' A. A  k  FIGURE  2.10  TOODOGGONE VOLCANICS  Section X,  Pliensbachian  biostratigraphy and lithostratigraphy  27  2.2.1 THE JOAN FORMATION; The  Joan  Formation is named for exposures  the  southern  shore  of Joan  the  Joan  figs.  2.3  and  2.4.  flow  of  the  Toodoggone  Formation, about  thickness  of about  siltstone  with  The  60  minor  Lake i n the 200  m  Joan  thesis  east of the  Formation  Volcanics  in  is  of  map area (fig. 1.2). south end of Joan  The  the  thesis  mudstone  map  area  type section  above  and  the  uppermost  a  maximum  attains  of medium bedded (10-30 cm thick beds)  and  silty  limestone,  and  a  thin  locally developed basal conglomerate  that grades laterally to pebbly sandstone  silty  is poorly sorted  shale.  grains  The  ranging  basal in  size  relationship between about  50% of the  grains are The  conglomerate from  fine  sand  grain size and degree grains, and about  conglomerate  size of the is clast  .or smaller grains  rock  cobbles.  of the  20%),  fragments  m m or less).  hand  source  specimen,  Fossils are ammonites Sedimentary  rare and  of much of the  many or  of  the  clasts  absent i n the  bivalves  structures  were other  is greater  not  does  chert.  than that  rounded to appear  The  of the  rock is made  Veins less than filled  angular  to  be  any  make  up  remainder of  the  about  5%).  mineral grains.  The  up of  1 m m wide are  fine  sand-size  common and  are  with calcite or less commonly with  volcanic material was from the underlying flows. In are  indistinguishable from  coarser  facies  found i n the than  There  m),  and possibly  and feldspar (chiefly plagioclase;  filled with calcite, quartz, or both. Pore space is chlorite. The  of  grains are  supported; less than 5% of the  (1/4  and consists  (<10  of rounding. Volcanic rock fragments  20%  predominantly quartz (about  average  to  of  Lake, is illustrated i n  discontinuously exposed  m. It consists primarily interbeds  examined in its type locality, around  poorly  of the  the  subjacent  conglomerate,  finer  sediments,  defined  massive  but the  indicating a bedding  flow  occasional  marine  (>1  m  rocks.  setting.  thick)  are  absent The sandstones Joan  upper that  contact  grade  Formation. The  of  rapidly  the  conglomerate  upward into the  lower siltstones  are  is  abrupt  siltstones  that  and  is  overlain  comprise  medium bedded, medium grey  the  bulk  by of  and weather  fine the to  28  medium  grey-brown. They  are compositionally less mature  unit due to higher organic and clay content.  than  siltstones  The lower siltstones  higher  i n the  are made up of about  40% angular to sub-angular monocrystalline quartz grains with less common (10-20%) grains. Plagioclase often  of  fine  grains make  sand  size  up about  comprise  10% of the rock,  about  5% of  consists of skeletal carbonate grains, opaque organic matter,  the  rock.  and volcanic rock Less  than  chert  fragments,  5% of the  rock  minerals, and chlorite. The matrix consists  clay minerals, and fine grained chlorite. The rock  has a high  of  percentage  of matrix (about 25-35%) but is clast supported. Siltstones  higher i n the unit are more  siliceous and compositionally more  They tend to be more brittle than the lower siltstones  mature.  and commonly show a polygonal  or columnar jointing pattern perpendicular to the medium (10-30 cm thick) bedding. The amount o f organic  matter  siltstones,  there  however,  and clay i n the matrix is less than is an appreciable  amount  o f cherty  that  seen  groundmass  that gives the higher siltstones their brittle nature. Patches and vein  i n the lower i n the matrix  fillings  of calcite are  The lower  siltstones and  common. Fossil fine  content  sandstones  varies  contain  throughout abundant  the siltstone  ammonites  sequence.  and  bivalves,  particularly  thick-shelled bivalve genus Weyla.  Higher i n the section the specimens  be  more  smaller,  trigonid  bivalves  are  common,  and ammonite  same. Near the top of the siltstone section the rocks are either  the  of Weyla  frequency  large, tend to  remains  the  unfossiliferous or contain  mainly terebratulid brachiopods which are locally very abundant Thin crystalline 5-10%  carbonate  calcarenite  interbeds containing  i n the  upper  80-85% calcite  siltstones spar,  silt-size quartz grains. The boundaries with  fairly sharp but show slight gradation i n thin calcarenite  beds  but colonial  and solitary  echinoids and bryozoans are found.  less  than  of  medium  10% shell  the sub- and superjacent  section.  corals,  consist  to  coarsely  fragments and siltstones are  Ammonites are uncommon i n the  bivalves,  gastropods,  brachiopods,  rare  29  Fining  upward grading observed i n the  sandstones  and conglomerates  in the lower  part of the Joan Formation is the only sedimentary structure seen i n the formation. The Volcanics surface  lower contact  is  erosional  does  not  as  of the Joan  Formation with subjacent flows of the  indicated by  the  represent  Acanthopleuroceras  cf.  A.  a  basal  significant  stahli,  has  time  been  conglomerate, gap,  but  this  erosional  as  the  same  however,  found in  the  Toodoggone  lowest  sediments  contact  ammonite,  of  the  Joan  Formation and from sediment interbeds i n the highest volcanics in an area about 20 k m north of the Deposition  thesis  of  the  map Joan  area  (locality 138,  Formation in the  (Lower Pliensbachian) as indicated by Carixian  as  fig.  indicated by  the  thesis  A. cf.  ammonites  1.1;  A.  H . W . Tipper, pers. comm.,  map area  began  early  in the  stahli, and continued to the  Dubariceras  freboldi  and  1985).  Carixian  end of  Aveyroniceras  (see  the also  chapter 4, biochronology). About  1  k m to  the core of the Lower  northwest of  the  anticline that dominates the  Pliensbachian  found. Here the  the  rocks  of  westernmost  exposure  of volcanic rocks in  thesis map area (localities 129-130,  markedly different  lithology to  that  described  fissile  although  sedimentary shales.  i n the this  form of veinlet  may,  laminations  Pyrite is  above  1.2), were  Joan Formation is a dark grey to black shale comprising 90-95% organic  matter and clays with about 5% very fine quartz silt, minor (<1%) and minor calcite  fig.  as  in  large  fillings  part  suggested  by  be  the  and calcispheres. due  to  distorted  uncommon. Ammonites found in the  plagioclase silt grains, This shale  tectonic preservation  shale  shearing of  is strongly rather  fossils  allowed for  than  in  these  correlation with  the Pliensbachian siltstones described above.  2.2.2  THE EAGLENEST The Eaglenest  headwaters  of  Formation is named for exposures examined at Section Y , near  Eaglenest  thesis map area,  FORMATION:  Creek  (fig.  1.1).  i n Section 1 (fig. 2.3).  The The  type  section,  however,  is  Eaglenest Formation is widely  located  in  the the  distributed in  30  the thesis map area and to the northwest (fig. 2.1),  and attains a thickness of 280  m in  the thesis map area. The  Eaglenest  weathering shale shales  are  carbonate  Formation comprises  with  three  composed of and chert  mainly dark  grey  to  black,  concretionary beds and minor tuffaceous  80-90% clay particles and organic matter.  make up about  10-15% of the  fissile  beds  to  blocky  or lenses.  The  Quartz silt and minor  rock, and silt-size botryoidal and/or  cubic pyrite grains may make up to 0.5% of the rock. The gullies, not  shales  observed  (approxomately  seen.  1  from the  section,  largely structureless.  is poorly defined and is on the  readily  results  are  in  cm)  outcrop  surfaces  separation  order of 40  but  the  parallel to  of  laminae  Bedding, where  shales  faint colour lamination and concentration  fractures indicate the presence Three  levels  of  100  cm  separate  bedding. According  in weathered  Blocky or flakey weathering shales  to  exposed  surface  to  in  creek  contains  the  along  closely  spaced  Spears  (1980),  fissility  exposures  of  Protogrammoceras.  shale. In  of grains along lamellar planes  thin  can  be  characterized by strong, closely spaced (1-3  cm)  of non-fissile mudstones i n the section.  calcareous  Upper  and  thick. Lamination was  concretions  are  present  within  the  shales  section. The lowermost bed occurs at about 15 m from the base of the and  beds  Pliensbachian  ammonite  genera  Arieticeras,  of  shales  the  type  (fig.  2.2)  Leptaleoceras,  and  A t 30 m the second concretionary bed contains the U p p e r Pliensbachian  ammonite  Lioceratoides  ammonites  appear  to  propinquum. form the  In  neither  nuclei of  the  of  these  concretions,  concretionary and  original  beds  shell  do  material  the is  rarely preserved. The ichnogenus infilled  with  L.  propinquum  Chondrites.  These  concretion  bed  traces are  sediment identical to  the  and do not cut across grain boundaries.  locally contains  trace  definitely burrows rather matrix, and the  walls of  fossils than the  referable borings;  traces are  to  the  they  are  irregular  31  Concretions i n the parallel  to  bedding, of  two lowermost concretionary beds maximum dimensions, usually  about  rock is fairly homogeneous  I m , but average  about  0.5-0.75  m. In  thin  section  the  and consists of fine grained calcite spar with silt-sized pyrite  cubes making up about 1 to 2% of the rock. Abundant unwalled calcispheres infilled with calcite spar of a slightly coarser moulds (Scholle, can be seen;  texture  than the matrix may represent infilled microfossil  1978). Rarely, remnants  of  the  original  wall structure  of the microfossil  these remnants appear to be of radiolarian tests. Thus in thin section  there  is some evidence for the replacement of radiolarian tests by calcite. The the  shale  Haugia.  third  and highest  sequence  These  and  concretion bed is  contains  concretions  are  Middle  found about  Toarcian  200  ammonites  different than those just  m above  including  described. They  the  base  Peronoceras are  of and  smaller (less  than 40 cm) than the lower concretions and weather to a light brown colour as opposed to  the  fossil  dark grey nuclei,  colour of  and  some  the  lower concretions.  concretions  consist  They  entirely  appear of  to have  large,  formed around  severely  recrystallized  ammonites. Shell material is quite commonly preserved i n these concretions, whereas pyrite is rare. In thin  section the rock consists of partly recrystallized remains of ammonites and  some small spherical structures infilled with calcite spar that probably represent microfossil moulds.  Patches  infillings  of  of  coarse  dissolved  calcite  spar  macrofossils  make  but  up about  evidence  of  25% the  of  the  original  rock  and  structure  may has  be been  obliterated. About grey-brown  20  m  weathering  ammonites crops o u t 60  above  the  lenticular The  Peronoceras concretion bed  lens is 3-4  of  siliceous  bed, a  mudstone  m thick and can be  resistant, containing  medium to Middle  light  Toarcian  traced no more than  about  m along strike. Ten to fifteen percent of the rock consists of angular silt-size quartz  and minor plagioclase grains. Unwalled calcispheres and microcrystalline silica spheres  about  0.1-0.5 m m i n diameter are common (1-2%). The matrix consists of a cherty groundmass  32  with  a  fresh  high content  surfaces.  The  (radiolarian?)  of  organic  matter  giving  high  silica  content  in  sedimentation  microcrystalline  and  silica spheres  a  the  this  moderate  provide evidence  rock  bed  is  influx for the  a  medium-dark grey  probably of  due  to  volcaniclastic  pelagic source  colour on  both  pelagic  material.  The  of silica, while  the  angular quartz and feldspar grains indicate a volcanic input The  lower  contact  lithologically abrupt with juxtaposition  of  these  of  the  Eaglenest  Formation  is  structurally  conformable  the underlying siltstones of the Joan Formation. The two  markedly  different  formations  suggests  that  but  stratigraphic  a  hiatus,  or  paraconformity of unknown extent may exist, but fossil control is poor i n this portion of the section. The age of the lowest shales i n the Eaglenest as  indicated by  the  ammonites  and Peronoceras suggest  Arieticeras  and  Formation is l a t e  Leptaleoceras,  a late M i d d l e Toarcian age  and the  Plienbachian  ammonites  for the top of the  Haugia  formation i n the  type section.  in  About  15  1.1  and  figs.  k m to the northwest of the 2.2  as  Section  and  Y,  pebbly  a  thesis  sequence  of  to  examined.  Middle  represents  a more proximal facies  than the shales i n the thesis map area, the  of which  is discussed  2.3  of this chapter.  sequence of Lower Toarcian siltstones, sandstones  Also  This  Toarcian  sandstones  et al. (1984) from an area  was  Lower  siltstones,  in section  sandstones  map area, on a hillside referred  and 2.2  shales, probably  significance  discussed in section  and volcanic breccias  referred to in figs. 1.1  sequence  to  2.3  is a  described by Smith  as Section  Z  (section  1  of  series  of  Smith et al.), about 40 k m northwest of the thesis map area.  2.2.3  THE GLADYS Resistant  FORMATION:  beds  of  the  Gladys Formation are  well  exposed  and form a  small waterfalls i n Gladys Creek which has cut a channel perpendicular to strike through the thesis map area and for which the formation is named (fig. 1.2). the  Gladys  Formation  is  located  in  Section  1  (fig.  2.3).  The type section  Thickness  of  the  of  Gladys  33  Formation is variable; the formation attains a maximum thickness well exposed i n the thesis map area where its resistant The  Gladys  calcareous  Formation  siltstones  and  fine  consists sandstones  grey-brown weathering sandstone fine  ripple  lamination  non-calcareous, a  higher  upsection  of  organic  of  the  Gladys  bedded  minor  the  siltstones  are darker i n colour and have  content  beds underlie prominent ridges.  medium  with  130 m , and is  (10-30  silty calcarenite  cm), beds.  siliceous Fine,  i n the lower portion of the unit is calcareous  whereas  and the dominantly  content  of  o f about  matter fine  Formation  show a more  and oxidized  restricted  except i n a few beds where they are abundant  to  lamination,  medium  and shows  tend  to  rusty weathering, probably  pyrite.  sandstones become is  parallel  Carbonate  more  resistant  dicoelitid  content  that  be  due to decreases  and siliceous.  belemnites  to  Fossil  are  sparse  In the western portion of the thesis map  area rocks of the Gladys Formation become less siliceous and finer grained. The Eaglenest  lower  contact  Formation  of interbedded  is conformable.  shale and siltstone;  last shale interbed. absence  of  Peronoceras  of the Gladys  Formation  The gradational  with  the  underlying  shales  contact is marked by a 5-8  the formation boundary  i n shales  The presence  of  late  underlying the Gladys  Middle Formation,  m zone  is arbitrarily placed above  The age of the Gladys Formation is not well constrained  ammonites.  of the  Toarcian  ammonites  the  due to the (Haugia  and dicoelitid belemnites  and within  the Gladys Formation suggest a Late Toarcian age.  2.2.4 T H E G R O V E S The found Groves  Groves  i n the  Formation is named  cirque  Formation  Volcanics  FORMATION: for the abundance  southeast of Groves  is situated just south  ;  Mountain (fig. 1.2).  of the westernmost  i n the thesis map area (around  formation.  The presence  The type  exposure  of the Groves  Formation  of this  locality  of the  locality 122, fig. 1.2). Thickness  not exceed 20-25 m , although this is difficult to determine the  of float material  unit  of the  Toodoggone  probably  does  due to the poor exposure  can usually  only  of  be inferred by  34  characteristic in  float  pieces of light grey  at the base o f the more  below).  Fragments  (.5-1.5  cm) bivalves  ammonites,  most  Formation the  Gladys  this  of the Groves that  notably  Formation  of  the  genus  commonly  place.  The ammonite  In places,  eroded  This  cm thick)  before  onto  commonly  external  thickness  moulds  of  Groves  o f the underlying of the Groves  further  i n the  of small  o f the  the deposition  found  found  (described  moulds  contact  is discussed  shale  Formation  external  The lower  unconformity  Tmetoceras  contain  the entire  away  siliceous  Walker  superimposed  Tmetoceras.  unconformity.  took  (<1  and distinctive  Formation  was completly  Formations  chapter.  resistant  platey  may or may not be  is an erosional  and Walker of  weathering,  i n section  2.4  Groves  Formation  on the slopes  o f Walker  indicates an Aalenian age for the formation.  2.2.5  THE WALKER The  FORMATION:  Walker Formation is named  for exposures  Mountain  i n the thesis map area (fig. 1.2), where  fig. 2.3).  It is widely  reaches about  exposed  i n the thesis  200 m i n thickness  thinly bedded to laminated (<10 by  its distinctive  normally, their  the type section  map area  a  maximum  laterally  is located (Section  and to the west  in the thesis map area.  The Walker  of 5  cm. The beds  for up to a  few tens  Bed thickness  are fairly  o f metres.  Formation i n the  lighter  coloured  spheres (.1-.2 The  lower  beds.  About  m m diameter)  contacts  of  the  5% of the dark  that probably dark  beds  beds consists  beds  owe their  the  upper  cm) than  of polycrystalline  represent recrystallized microfossils  are sharp,  contacts  are  distinct but  convoluted i n places. The lighter coloured beds consist almost  of a microcrystalline  quartz  plagioclase  containing  about  quartz  (radiolaria?).  irregular and almost  groundmass  field  and maintain  colour to a high clay mineral and organic content, and are notably thinner ( < 1 the  is a  is 0.5 to 3.0 cm  continuous  The darker  1,  (fig. 2.1), and  cm) siliceous shale that is easily recognized  banding and reddish-brown weathering.  reaching  thickness  examined  entirely  10% angular, silt-size quartz and  grains that grade upward from the irregular upper contact of the dark  beds.  35  Besides sandstone  the  fining  upward observed  in thin  section,  some  fine  grained  calcareous  and siltstone beds occasionally found i n more southerly exposures of the Walker  Formation  display  fining  upward  grading.  Soft  sediment  deformation  of  the  beds  is  manifest by convolute slump structures. The  lower  gradational  with  contact  the  of  the  Walker  underlying Groves  Formation  Aalenian or Early Bajocian  poor at  ammonites  The  Stephanoceras  the formation indicate a late Early Bajocian  2.3  FACIES C H A N G E S  Spatsizi Group have  facies changes of  facies  ammonite  in the  changes faunas  type  although  and Teloceras  probably  section,  the  faunal control  found near  the  top  is of  age.  been  of this chapter the lateral variations i n the rock units of described. In  Spatsizi area  in  in age,  in the  and  A N D DIACHRONTSM  In the preceding sections the  conformable,  Formation. A t its base  Walker Formation is Late this contact  is  Spatsizi  collected  a summary and analysis of  is presented. It should be  was  during  this section  the  made  possible  course  through  of this  noted here  that  correlations  based  study and during  the  recognition  earlier  on  field  the work  in the area by the Geological Survey of Canada. The most profound lateral variation i n lithology is seen Pliensbachian-Bajocian  Toodoggone  in the transition from  the  volcanics on the southern flank of the Stikine A r c h  to  the basinward sedimentary Spatsizi Group equivalents to the south (figs. 2.1  and 2.2).  southward change  from an active  environment is  also  the  reflected  in  clastic components  sedimentary  of the  volcanic region to a marine sedimentary units  themselves  in  that  the  volcanogenic  and  units decreases southward into what is believed to be  This  coarse a  shale  basin now covered by Bowser Lake Group sediments. The of  Late  northward transition from  Pliensbachin  Pliensbachian  comprises  to the  Middle  fine  to coarse sediments  Toarcian  lowermost  shales  age. and  In  the  is best seen  thesis  concretionary  map shales  area of  in  sediments  the the  Upper Eaglenest  36  Formation,  and  is  directly  underlain  by  Lower  Pliensbachian  siltstones  of  Formation. Ammonites found in float at Section X , 10  k m north of the thesis  (fig.  consists  1.1),  indicate  that  the  Upper Pliensbachian  Lower Pliensbachian (Joan Formation siltstones)  there  i n the  thesis  of  map  strata area,  thus  shales of the  Eaglenest  replaced  at  by  Section  Y  epiclastic  siltstones,  more proximal environment, but are farther  to  the  interbedded  in  northwest volcanic  including Lioceratoides From  the  lithologically in the at  map area  X,  10  northwest  at  Formation  of the  the map  same rock area  proximal  and  unit the  to  Y,  thesis  that  that  the  is a diachronous  unit  north,  although map area  mixed  it  and has  and the  clastic/volcanic  resulted  of  the  outlined above in a  Arch and the establishment A  the  In  It  to  not  been  firmly  whether  rock  all indicate  the at  unit an  northward transgression  northwest  represent faunas.  Still  fauna  defined  its southernmost  exposure  Pliensbachian  established  in  in  age  that  Section  the  Joan Y  Formation of  the  Z  distal  represent  diachronism and  marine  waters  onto  age  farther  sequence at Section  Joan  The  as  are thesis and  northward (or the  basin Stikine  of a shale basin south of the Stikine Arch.  similar sequence of events was reported by Tipper and Richards (1976) for  southeastern  portion  of  a  breccias  Toarcian  overall rise in sea-level of  Toarcian  volcanic  M i d Toarcian  sandstone/siltstone  sequence  that  Formation,  is Late  Early  the  et cd., 1984). Joan  is  same  and  Pliensbachian-Early  sp. (Smith  appears  Similarly, it is uncertain  facies trends  subsidence)  it  sandstones,  Late  and Dactylioceras  area,  variations, respectively,  shallowing  a  sandstones  area  farther  as indicated by their  siltstones,  yielded  discussion map  Z,  are  pebbly  it is Early Pliensbachian i n age.  km  Section  and  area  dominantly marine  rocks  propinquum  foregoing  sandstones,  Section  flow  in the thesis  thesis  Section  at  map  map  indicating a  Lower to M i d d l e  thesis  Joan  identical to  northward coarsening of the Upper Pliensbachian sediments. The Formation i n the  the  the  Bowser  Basin  where  Sinemurian  and  Early  the  Pliensbachian  subaerial volcanics of the Telkwa Formation are conformably to disconformably overlain by volcanogenic  marine  sediments  and  minor  volcanics  of  the  Pliensbachian  to  Bajocian  37  Hazelton  Group.  Lithologies  lithologies of age trends  are  breccias more  for  that  to  both  example,  lose  shaly  the  Hazelton  equivalent rocks of the  common  Formation,  of  their  volcanic  sediments  (Tipper  of  The  not  Pliensbachian  volcanogenic  character and  do  necessarily  correspond  to  Spatsizi Group, but a few of the overall facies  sequences.  consists  rocks  and  to  sediments,  grade  Richards,  M i d Toarcian tuffs,  volcanic  northwestward  1976).  The  flows  and  basinward)  into  initiation  sedimentation was a result of an Early Pliensbachian transgression, the Joan Formation sedimentation in the thesis map area (see  (Le.,  Nilkitkwa  of  Nilkitkwa  as was the initiation of  also section  2.5).  2.4 UNCONFORMITIES The the  Stikine  Early  and  Arch  was the  Middle  Jurassic  dominant and  had  tectonic a  element  profound  in the  influence  Spatsizi area  on  the  volcanic  sedimentologic history of the area. In the preceding section of this chapter, and the distribution of units within the Stikine  Arch.  In  this  Group,  and  whose  section  origins  several  were  and  facies changes  Spatsizi G r o u p were discussed with respect to the  hiatuses  also  during  related  that to  have the  been  tectonic  recognized  in the  mobility of  the  Spatsizi  arch,  are  between  the  detailed. The uppermost the  Joan  surface  oldest  hiatus  flows of  the  laterally into  The  thesis  Toodoggone  does not represent  upper  the  map  volcanics  Formation. A s previously mentioned,  disconformity. The  the  in  surface  elastics.  The  of  volcanics  paleotopography  the of  is  the  and  the  erosional  contact  Lower Pliensbachian  faunal evidence  indicates that  siltstones this  the  developed at the contact is discontinuous and  conglomerate and  volcanics  is  the not  was finer  presumably elastics  believed  to  deposited  collected be  the  on result  higher  of  a  a  grades  i n depressions the  of  erosional  a significant time gap and is referred here considered to be  basal conglomerate  finer  area  in  areas.  significant  pre-Spatsizi G r o u p deformational event, but rather, was due to differential erosion of, and deposition on  an originally irregular volcanic  terrane.  Evidence  contrary  to  a  pre-Spatsizi  38  Group deformational 1)  There  is no  event is twofold: significant time  gap, if any, between  the  volcanics  and the  sediments,  therefore a structural event would have had to have been very short-lived. 2)  The  volcanics  concordant  and  overlying  H a d there  an angular discordance A  disconformity  approximately southwest  the  should be  trace  of  intervening  may  a  are  hiatus  Formation  in  paraconformity. the  variable  of  regional  local  the  thesis  The  sub-Aalenian  thickness  Walker Formations. found  about  7  km  the  deformational  boundary. Evidence  or  present,  erosional  on  at  has  been  and  absence  Lower  flows  the  or  is  of  recognized here  1.2)  of  Formation,  very  where  or  strata in  southwest  is  the  Toarcian thesis  manifest  subjacent  the  the  slow  the  Middle  was  or  found,  stratigraphically  part of  the  deposition  of  area  Toodoggone  underlying units of the Spatsizi Group prior to the  Walker  Formations.  sub-Aalenian  base  to  as  Gladys  of  the  the  map on  a  Groves  sub-Aalenian  thesis map Formation  deposition of the  area  the  Eaglenest  2.1)  volcanics,  the  had  Groves  and have  Formation,  Walker  indicating the  and  Formation erosion  deposition of the Groves  disconformity had more  by  which  and Walker Formations  (fig.  all the  the  in the  Groves  shales  map  at  referred  Lower Pliensbachian  than any of the older breaks i n the  Eaglenest  Toarcian  i n the  overlies  Clearly, the  of  evidence  contact is covered  least in part  event  paraconformity  southeast of  event,  fig.  the  Lower  removed by erosion prior to the  directly  structurally  floor.  area,  even  be  for this is found in  124-128,  flows, although  Within the thesis map area,  resting to  map  and  been partly or completely  been  extent  to  shales of the  is only recognized  topographically high feature on the sea A  within the  Pliensbachian  that they  represent  appear  apparent  to rest on Toodoggone  form. This disconformity  and  Group  thesis map area (near localities  possibility remains  condensed area  No  siltstones  pre-Spatsizi  L o w e r / M i d d l e Toarcian  shales appear  inaccessable.  a  is inferred to exist  portion of the  Toarcian  but  at the  been  Pliensbachian  of and  far-reaching  effects  Spatsizi Group record. In the vicinity of the  Skeena  39  Arch  in  the  Toarcian varies  southeastern  Nilkitkwa  in  age  Bowser  Basin,  Formation and the  from late  Middle  the  contact  overlying  Toarcian  to  between  Smithers  Early  the Pliensbachian-Middle  Formation (the  Bajocian)  is  also  base of  which  disconformable i n  many of the sections examined by Tipper and Richards (1976). The top of the with  the  (Bowser  overlying Lake  Spatsizi group is defined by a slight ( < 5 ° )  black  Group).  shales  This  and conglomerates  discordance  is  of  the  visible from  angular discordance  Bathonian Ashman Formation  a  distance  on  a  few hillsides  within the thesis map area and is seen at several other localities outside the thesis map area ( H . W . Tipper, pers. comm., 1984).  2.5 D E P O S I T I O N A T, H T S T O R Y O F T H E SPATSTZT  2.5.1  INTERPRETATION: Deposition  resulted  from  of the  a  THE JOAN  FORMATION  Lower Pliensbachian basal  transgression  volcanics. Whether the  GROUP  that  covered  upper flow surface  the  conglomerate  upper  flow  of  the  surface  of  Joan Formation the  Toodoggone  was subareally exposed or covered by shallow  marine waters prior to transgression is uncertain. Deposition of coarse and  fine  sediments  of the basal unit i n depressions and more elevated areas of the upper flow surface, from which  most  sandstones basal  of  the  was  and lower siltstones  conglomerate  fining-upward sudden  detritus  and  of  the  with  The  the  fine  followed  by  Formation. The fine  sandstones,  the  deposition of  abrupt contact together  the  fine  between  with  the  the rapid  sandstones to the lower siltstones indicates a fairly  environment  conglomerate  was  Joan  overlying  transition from the  transgression.  environment  derived,  deposition  changed and  from  low  a  faunal  shallow  (possibly  diversity to  a  nearshore)  deeper  water  environment of fine sand and silt deposition in which abundant, large sized specimens  of  the  to  bivalve  increase  with  Weyla the  and  frequent  deposition of  ammonites  the  were  upper siltstones  present. of  the  Water Joan  depth  continued  Formation. The  finer  40  grained and more mature sediments of the upper siltstones indicate that the source of detrital  material  sorting  and reworking before  reflect  periods  of  clastic source  is  away  or  that  the  deposition. T h i n  clastic  A deeper  influx  and  sediment  undergoing more  limestone  interbeds  may  indicate  water environment of  by the smaller size of the  was  also  i n the a  distant  deposition for the  few specimens  upper  of Weyla  or  Near the  dominated  abundance coarser  of  by  top of abundant  terebratulids  grained  the  Joan  terebratulid  indicates  sediments.  Formation the  The  a  terebratulid  According  shallow water  beds  at  siltstones low  the  to  Trigonia,  Taylor  setting  top  lying is  found i n these rocks,  fauna becomes either very  brachiopods.  nearshore  intense  upper siltstones  with the higher incidence of infaunal bivalves such as Pholadomya,  Myophorella. or  farther  reduced  area.  also suggested together  was  the  of  and sparse  (1982),  an  usually comprising  the  Joan  Formation,  however, are  dominantly siltstones as described above, and may represent shallowing i n an  offshore  not subject to coarse clastic influx, or nearshore  source  area area.  The  depositional  and  environmental  patterns  deposition close  described  here  Formation  and  to a low  correspond  to  those outlined for the Joan Formation by Steel (1984).  2.5.2  INTERPRETATION: The  contact  THE EAGLENEST  between  the  shales  FORMATION  of  the  Eaglenest  the  underlying  siltstones of the Joan Formation is abrupt and is structurally conformable. Whether or not the  contact  Joan  Formation  increase nature  represents  a  stratigraphic break  siltstones  and an associated of  sediment  the  environment  composition,  microfossils,  and  examined here  trace first  to  the  change of  is unknown.  Eaglenest  shales  represents  a  transition from  significant  water  depth  in depositional environment In order to determine  deposition  of  the  the  and  fossil  content  (including  fauna  of  Eaglenest  sedimentary  structures,  fossils)  considered. The  are  In any case, the  Eaglenest  the  shales,  factors  such  the as  macrofossils, Formation is  41  Modern  marine  according to the three  biofacies  aerobic  (>1.0  1984).  These  faunal  composition, and  pyrite  content  biofacies  of  can  the  Field  be  their  been  divided  Eaglenest  observations  existence  shales  m l dissolved 0 / l  The  rock  record  based  deposition  i n an  and micropalaeontological analysis or microfossils are  i n these  muds. A  dysaerobic  low diversity fauna,  suggest  rare;  generalized  sediment;  2  i n the  richness.  three  sediment),  2  (<0.1  into  the  few poorly preserved  ammonite  from  the  impressions  sequence  (fig.  2),  fossils  were  below  found  found  the  in  in  the  the  shales.  Peronoceras  concretion Near  concretion  beds, the  bed,  a  to  fabric,  dysaerobic  shale  show  environment  radiolaria and  a  that  would single  by bottom conditions.  several  190  ml  dark colour, and  the  a toxic bottom  (0.1-1.0  sediment  anaerobic of  The  (Savrda et al.,  on  dinoflagellate cyst found i n the shales would not have been affected Apart  biofacies  i n the sediment pore waters.  dissolved 0 / l  recognized  species  infaunal or epifaunal macropreclude  ml  sediment), and anaerobic  2  environment  have  amount of dissolved oxygen is present are;  dissolved 0 / l  environments  m  sample  poorly  level of  in  dark  preserved the  shale  grey,  fissile  and pyritic shale was collected containing a single indeterminate ammonite mould associated with  numerous  small  onto and scattered  (3-7mm)  bivalves.  The  bivalve  impressions  around the ammonite mould, and all the  are  both  superimposed  fossils are concentrated  along  a single bedding surface. Isolated specimens of the same bivalve were also found i n shale samples  devoid of  Toarcian  larger  Posidonienschiefer  Pseudomytiloides. dominantly  It  is  anaerobic  1978).  In  under  dysaerobic  follows,  any  southern  then,  in  widely to  conditions the  The  Germany, accepted  dysaerobic  British  that  fossils.  bivalves  including that  conditions  Columbia, certain also  presence  the  contain of  the  resemble  genera  facies  of  bivalves  bivalves  in  and the  deposition i n an anareobic to dysaerobic bottom environment  (or  were  Seilacher, Fernie  (Hall the  those  Bositra  Posidonienschiefer (Brenner  these  these  closely  and  found i n Posidonia) deposited  1978;  Formation Stronach,  Eaglenest  shales  the and  under  Kauffman, deposited 1982).  It  indicates  42  The Brenner  mode  of  and Seilacher,  epibyssate-benthic these  bivalves  represented rather,  1978;  (or benthic  are  they  not  lived  above  favour the  became  dislodged  subsequently  1983;  1965). Pseudoplanktonic, planktonic, and  to  shales,  the  have  in  the  anaerobic  bottom  environment  the Posidonienschiefer, and the Fernie Formation, but  stagnant  observed  lived  bottom.  association  It  is  likely  between  that  they  could  bivalve and ammonite  tolerate  impressions  shales could indicate either a pseudoplanktonic or benthic island mode  However, common to  debate (Tenabe,  island) modes of life have all been proposed. In any case,  thought  conditions. The  in the Eaglenest  seem  Jeffries and Minton,  by the Eaglenest  dysaerobic  life.  life of these bivalves is a subject of some  v  stra/  bivalve fossils  found isolated from any  pseudoplanktonic model. These 'strays'  from  their  host  (possibly  a  floating  may piece  larger  of  fossil would  represent  individuals  that  of  or  and  sank into the poisonous depths below. However, none  wood  algae)  of the common  pieces  of silicified wood found i n the section show any sign of colonization by epizoan bivalves. The  life  mode  controversy  cannot  be  solved  based  on  the  Spatsizi  collections,  but  the  evidence does support the interpretation of an anoxic depositional environment The  trace  fossil  Chondrites  which  is  found  in  some  of  the  concretions  may  indicate a somewhat more oxygenated environment of deposition for that particular horizon. Brenner  and  contain  abundant  events  during  occurred. describe Santa  trace  Monica,  Eckdale  of  report They  colonization  interpretation  is  fossil gradients  several  interpret of  the  supported  from aerobic  (i.e.,  less than 0.1 of  slightly  trace higher  by  the  to  (0.1-1.0 that  ml  the  Posidonienschiefer  representing by  periodic  Chondrites  work  anaerobic  of  Savrda  sediments  et  by 0 /l 2  Chondrites  sediment)  infaunal sediment)  al.  i n the  that  oxygenation  forming  coast of California. The 2  created  within as  sediment  m l dissolved 0 / l  fossils  (1984), however, consider  levels these  and San Pedro basins off the  appearance  sediments  (1981)  Chondrites.  which  This  as anaerobic first  Seilacher  organisms  (1984)  who  Santa  Barbara,  sediments  classified  contain no trace fossils.  burrowers  occurs  oxygen  content  in  dysaerobic  Bromley  is found i n all environments,  The  and  including  43  anaerobic  environments. The view that Chondrites  is maintained here summary, shales  the  is  i n light of the  impressive data presented  apparently limited occurrence  probably  a  result  is not found i n true anaerobic  of  of Chondrites  short-lived  by Svarda et al. (1984). In  to certain levels in the Spatsizi  oxygenation  events  that  dominantly anoxic depositional environment represented by the Eaglenest Sedimentary includes the  evidence  supporting the  dark colour, pyrite content,  anoxic  the  sediments  interpretation  fissility of some  of  punctuated  the  shales.  the  Eaglenest  shales  of the shales, and the  faint  colour lamination and concentration of grains along lamellar planes as seen in thin section. The  dark  organic  colour  matter  prevented  is  imparted by  i n the  the  shales  destruction  of  organic  matter  preserved  was possibly facilitated organics  on  the  by  seafloor  in the anoxic  by  rock.  bottom  deposit  Accumulation of conditions  feeders  and  which  bacteria.  Faint colour lamination and the concentration of grains parallel to lamination seen i n thin section  suggest  an  absence  of  bioturbating  infauna, presumably  due  to  inimical  bottom  waters. Although Fernie  similar  Formation  and  in the  deposited fairly rapidly  many  time  (Hall  with  and  Paper  Shale  division  black  shale,  ranges  of  respect  classic  the  1982).  Fernie 10  the  and  black  67 and 400  thick  appear  m.  Accumulation of  indicates  that  the  magnitude greater Eaglenest poorly  shale  this  sedimentation  thickness rate  for  of  of  (Frebold,  sediment  the  to  as  have  the been  thickness  m and deposition spanned much Toarcian  thin  Spatsizi  over  1969). The  this  shales  was  Poker  bedded,  Upper Pliensbachian to Middle Toarcian portion of the Spatsizi shales 150  such  For example, the  More specifically, the  m  sequences  shales  sequences.  Formation, consisting 30  shale  Eaglenest  to these other  between  Stronach,  between  to  Posidonienschiefer,  of the Fernie Formation ranges Jurassic  respects  short  Chip,  or  grey  to  of  the  dark  thickness  is on the period  perhaps  an  of  order of  of  time  order  of  than i n the Fernie Basin. It is possible that rapid sedimentation of the  was due to sedimentation  in a tectonically active eugeocline, and that  developed lamination in these shales  was the  result of  rapid burial  under  the  anoxic  44 conditons. According  to  in the upper 10-15 and  experience  the  presence  pyrite  in  Curtis (1980), bituminous shales  undergo intense  the  alteration  m of the sediment column, i n the sulphate reduction diagenetic zone,  continued alteration below this i n the of  diagenetic  'aggressive'  Eaglenest  solutions  shales  dissolves  probably  fermentation  unstable  formed  in  diagenetic  minerals  the  in  sulphate  the  zone  where  sediments.  reduction  zone  The where  bacterially reduced sulphate in the pore waters may react with any ferric iron present form  pyrite.  Fluctuations  activity of the  bacteria  in  the  pH  of  of  pore  were probably responsible  material as well as, conversely, for the preservation  the  radiolarian  tests  in  fluctuation, however the 'aggressive'  waters  for the  resulting  from  shales  metabolic  dissolution of calcareous  formation of the calcareous  these  the  may,  in  concretions.  part,  be  due  to  skeletal  The  to  poor  this  pH  solutions of the fermentation diagenetic zone may  have  been more effective in their destruction. The Eaglenest  anoxic  shales  anoxic event had  some  have  condition  is consistent  during the  influence  been  from  sedimentologic  on  facies  and  and  faunal  evidence  with data indicating a world wide eustatic sea-level  Toarcian (Hallam, 1981;  responsible  Posidonienschiefer  inferred  development,  for  the  deposition  the  Fernie  Sellwood, 1978). Although  an of  Formation  absolute  rise  bituminous are  two  in sea-level  facies  examples  around of  in  rise and  local is  tectonics  thought  the  globe.  bituminous  rifting  rise  and  mid-oceanic  (Hallam, dispersal  1981). of  Sellwood  Pangea;  ridges resulted in the  (1978)  increased  attributes seafloor  displacement  the  Jurassic  spreading  of ocean  water  eustatic  rates  and  out of the  to The  Toarcian  sediments. The Toarcian event is just one transgressive phase i n an overall Lower sea-level  the  Jurassic  events  to  growth  of  ocean  basins  and onto continental areas. The  relationship  between  anoxic  events  and  transgression  is  linked  to  local  bathymetric configuration (for example, the flooding of a silled basin) and to the position and  magnitude of the  oxygen minimum layer.  According to Jenkyns  (1980),  transgression  45  leads  to increased  greater  bacterial  organic productivity i n epeiric  oxidation below  the  photic  zone.  oxygen minimum layer, formed by bacterial in the the  and shelf Vertical  seas, which  in turn leads  and  spreading  lateral  oxidation, would cause a general  worlds oceans. The absence of polar ice caps and the equable  Early Jurassic  minimizing floors  the  (see  flow  (Sellwood,  chapter of  cold,  1978;  oxygen-minimum  layer  5)  would  oxygen-rich  Jenkyns,  and  have  polar  1980).-  an  absence  faunal  and  augmented density  The  of  the  oxygenating  anoxic  the event  climate inferred for  effects o f transgression  currents  combined  of  along  effects  bottom  to  the  of  currents  worlds  by sea  an  expanded  resulted  in wide  spread anoxic conditions. In  summary,  the  sedimentologic  together with well  documented evidence  all  a  point  overall  towards  anoxicity  of a benthic  dominantly  character  anaerobic  to  was probably punctuated  dysaerobic  by short  environment  The with  respect  deposition  However, (1982),  to  the  during  belemnites,  the  according  and  Eaglenest Late  little can be  the  THE GLADYS  ripple laminations  to  association  Formation,  said of the the of  faunal belemnites  ammonites indicates a fairly nearshore  In  coarse  the  the  scarcity  the  erosional  fine  the  deeper  marine  The  and poor  The  absence  preservation  factors.  shales of  size  of  shoaling of  all  distribution  sandstone,  or shallow water  unconformity of regional extent  deposition of  event  deposition.  events.  the  Gladys Formation,  event  fossil  of deposition based  lithologic  with  a  absence  environment and  grain  indicates  As discussed previously i n this chapter, is an  shales  FORMATION  relatively  Toarcian.  Eaglenest  of  lived oxygenation  fauna is largely due to anoxicity whereas  INTERPRETATION:  the  of a worldwide Toarcian transgressive/anoxic  of planktonic forms is attributed to post-depositional diagenetic  2.5.3  of  data  together  in  types on  the  basin  of  except  for  the  faunal  presented with  an  evidence. by  Taylor  absence  of  environment  the upper contact of the The  shoaling event  the  Eaglenest  that  Formation  Gladys Formation effectively and  ended  led to  the  46  deposition of the  Gladys Formation may also have  Gladys Formation and, in some  ultimately led to  cases, older units, prior to the  the  erosion  deposition of the  and Walker Formations. Tipper and Richards (1976) and Carter (1985) have major  regressive  phases recorded  i n sequences i n the  the Queen Charlotte Islands, respectively. It to a global sea-level  2.5.4  THE P R O W S  to the  Aalenian to  regression (1985),  and  Bajocian  stage  beds  clay-sized  of  by  a  and  this shoaling event  reported  is  area  density  reported  was  beded  Formation radiolarian  bioturbating  flank of the  settled  Formation  out  rocks  shallow slopes  currents  a  like  by  Tipper  and  reflects  global  sea-level  time  tuffaceous were tests?)  of  both  formed  in  the  a  change.  basinal  and  anoxic  from volcanic activity probably centred  i n the  probably sedimentary  and seismic activity i n the  Middle  Bajocian.  of the  formed  by  convolute  slump  movement; of  structures  semi-coherent  basin. Movement may have  been  The where  interrupted along  dark shale  in  the beds  tuffaceous  the  Walker  sediment  triggered  by  by  down  volcanic  area.  volcanism and  Regional  sediment  shale  environment  resulting  Soft  Early  setting  frequently  irregular upper surfaces  Carter  The  volcanism  an  was  (1976),  This  The  sedimentation  in  Toarcian  Walker Formation.  quiet  accumulated  Late  Richards  explosive  shales of  the  Formations  infauna.  Stikine Arch.  quickly.  were  Toodoggone  related  by the sub Aalenian paraconformity,  and the fining upward grading i n the light coloured tuff beds indicate that the material  and  FORMATIONS  Aalenian transgression,  probably  i n the  Walker (and  A N D WALKER  This  been  Spatsizi  recorded the  age.  has  (1981),  the  as  falls and  southern  above,  particles  undisturbed ash  in  that  initiated the deposition of the Groves and Walker  Bajocian  Hallam  sedimentation dark  Early  discussed  Groves  southern Hazelton Trough area  is possible  erosional period represented  renewed marine transgression of  also  the  drop postulated by Hallam (1981) for the Late Toarcian.  INTERPRETATION: Subsequent  of  Spatsizi  G r o u p sedimentation  uplift subsequently  resulted  in the  came  to  a  close  angular discordance  in  the  observed  47  between  the  molasse-type eugeoclinal  Walker Formation of  the  sedimentation  Bowser  volcanism  and  of  the  sedimentation  beginning of a new tectonic regime  Spatsizi G r o u p and the Lake  Group  previously active  was  Bowser in  in the  Lake  marked region,  for the northern part of the Stikine  Group.  contrast  The  to  the  and marked  the  terrane.  3. S T R U C T ! J R A L G E O L O G Y  3.1 F O L D S Structure  in the thesis  map area is dominated by a large, west-northwest  trending,  open to close, upright anticline whose axial plane dips steeply to the northeast trace of the and  anticline transects the  southeast for a total  distance  map area and can of about  40  be  traced  k m (fig. 3.1).  farther  Within  anticline is doubly plunging and is cored by flows of the Toodoggone  during  The  Toodoggone  volcanics  the  formation of the  and the  overlying Spatsizi sediments  anticline, due to the  viscosity contrast  to the  the  volcanics  fold.  and  tuffaceous  sediments  of  the  complexly deformed than the  of  overlying  a  broad, open  Spatsizi  and  Bowser  map  between  the  development  The  Lake  northwest area  behaved  rigid nature,  in the  axial  the  volcanics.  and overlying sediments. Because of their relatively competent resulted  The  differently  the  volcanics  deformation  dominantly Groups  are  volcanics. Development of tight minor folds in the  of  shaly more  sediments  is common on both limbs of the anticline. Folds  in  the  map  area  have  a  parallel  form,  that  is,  there  is  no  appreciable  thickening or thinning of the units i n the core or limbs of the folds. M u c h of the strain has  been  taken  up through  flexural slip primarily along surfaces  separating  lithologic units. The best developed examples of this can be seen between volcanics  and the  overlying Lower Pliensbachian  Formation, and between the resistant overlying  Aalenian to  These contacts are  Bajocian  Upper Toarcian siltstones  tuffaceous  conspicuous i n the  conglomerates  shales  field  of  and are  the  and  siltstones  and  preservation  due to the surface.  of  slickensides  and minor brecciation.  erosion of the less resistant  Flexural  slip  also  resulted  in  Toodoggone of  Walker  the  Joan  Formations.  by prominent dip slopes  the underlying u n i t Flexural slip occurred along these dip slope surfaces local  the  different  (Gladys Formation) and the  Groves  manifest  the  Exposure  of  of  as evidenced by  these  dip slopes  is  overlying units above the flexural slip (dip slope) the  48  development  of  slickensides  on  the  more  4 LEGEND Thrust fault Normal fault Anticlinal axial trace Synclinal axial trace j J V  V  V  V  V V Y Y  Bowser Lake Group sediments Spatsizi Group sediments Toodoggone volcanics  10 Kilometres  FIGURE  3.1  -I  /  Northern Limit ol Groundhog Coalfield  \ V.  Map showing the major rock units and structures in the region surrounding the thesis map area (modified from Gabrielse and Tipper, 1984).  50  resistant,  and generally more  calcareous  beds  within  the  Toarcian shales  of the  Eaglenest  Formation. A  series  structural  of cross-sections  relationships  through the  between  the  units  anticline (fig. 3.2a,  present  progressively tighter from the northwest to the plane  of  the  evidenced by  anticline field  appears  section  be  the  southeast  steeply  area.  within  dipping  The the  illustrates the  anticline  line (figs. 3.3b,  diagrams) constructed  (fi  (75°-90°)  from  to  d, and f). A more accurate  field  becomes  map area. The axial the  northeast  relations of the axial trace with topography and analysis of  of bedding plane intersections each  to  in  c, and e)  as  stereoplots  data in the vicinity  determination of the  of  orientation  of the axial plane is beyond the scope of this thesis. Bustin and Moffat (1983) and Moffat and Bustin (1984) have the  stratigraphy and structure  the  thesis  map  Jurassic/Lower sedimentary Bowser  area.  The  Cretaceous  sequence,  of the  Groundhog coalfield 20  Groundhog  (Callovian to  referred  Lake Group sediments  to  as  coalfield  is  underlain  Albian) marine the  Gunanoot  that overlie the  to 40  and  described in detail  k m to the  by  Middle  non-marine  assemblage,  Spatsizi sediments  is  south to  Upper  sediments.  correlative  in the  thesis  (Bustin and Moffat, 1983). Structural analysis of the Gunanoot assemblage  of  This  with  the  map  area  has shown that  these rocks have undergone two phases of deformation (Moffat and Bustin, 1984). Analysis of structural data from the  Spatsizi sediments  i n the  thesis  map  area  indicates  that  this  stratigraphically lower sequence of rocks has experienced the same deformational history as the younger Gunanoot A  contoured  assemblage. stereoplot  northwest trending first phase about fold  a axis,  second  phase  fold  resulting in the  (fi  diagram)  of  the  Spatsizi  lineations (bedding intersection axis  oriented  fanning out  of  approximately these  storeoplot (fig. 3.3a). This relationship between that outlined for the Gunanoot assemblage  first  data  shows  lineations)  perpendicular  lineations  along  a  that  originally  have been to  the  first  small circle  rotated phase in  the  and second phase folding is similar to  (Moffat and Bustin, 1984;  fig.  3.3b).  51  3.2  FAULTS Faulting played a significant rSle i n the structural development of the Spatsizi area  as  a  been  whole, but found  exposed  surrounding (Gabrielse  only one  the  in  thesis  fault of  the  displacement)  have  map  map area  and Tipper, 1984) been  more  than  area  are  a  itself.  few  tens of  Traces  indicated on  of  the  metres  large  bedrock  displacement  thrust geology  faults map  and thrusts of similar magnitude (generally less  mapped in the  Groundhog coalfield (Moffat  in  has areas  of Spatsizi than 1 k m  and Bustin, 1984).  Tipper and Gabrielse (1984) have mapped thrust traces immediately to the south and to the north of the thesis map area (fig. 3.1), thesis map area whose trace  itself. This suggests  does not come  cross sections  that  to surface  although no thrust traces were found in the  the thesis area is part of a larger thrust sheet  anywhere  within  the  thesis  map area.  Interpretive  constructed by Moffat (in prep.) for the Groundhog coalfield show that  the  coalfield consists  of imbricate, dominantly southwest dipping thrust sheets. M o f f a t calculates  the  surface  detachment  volcanics.  A  of  the  thrusts  similar thrust surface  is  to  be  assumed  stratigraphically  to  be  present  below  the  some  depth  at  Toodoggone below  the  volcanics exposed i n the thesis m a p , area. North-south between  a  trending,  few metres  steeply  dipping  faults  to a maximum of about  with  100  vertical  displacements  m are recognized in the  ranging  map area.  The western block of these faults has been downthrown, but the dips of the fault planes have  not  been  determined.  Small  scale,  north-south  trending  faults  of  about  3-10  m  displacement have been observed cutting the uppermost surface of the highest flow of the volcanics. These  faults  die out rapidly  i n the  overlying  sediments,  the  strain presumably  being taken up through deformation in these less rigid rocks. Trending western  block  stratigraphic conglomerate  perpendicular to has  dropped on  units present of  the  in the  the the  fold order  area,  axis of  from  of  the  anticline is  100  m.  This  the  fault  Toodoggone  Ashman Formation. Movement on this  a has  single  fault whose  displaced all  volcanics up to  fault therefore  the  occurred  the  lower later  52  FIGURE  3.3  C o m p a r i s o n of structural data f r o m the thesis m a p area (fig. 3.3a) with the northern G r o u n d h o g coal field (Hg. 3.3b; f r o m M o f f a t and B u s t i n , .1984). F i g . 3.3a is a contoured stereoplot o f b e d d i n g plane intersection lineations O diagram) from the entire thesis map area; fig. 3.3b illustrates bedding to first phase clevage intersections from the G r o u n d h o g coal H e l d .  53 than Bathonian  time. The  orientation of this fault is parallel to the inferred trend of  second phase fold axis, suggesting  that it may be  related to the second  Outer  to  phase  arc  resulted  in  extension angle  extension the  perpendicular  formation  faults  of  fault i n the  of  this  second  fault  similar orientation thesis map  the  In  and  the  axis  Groundhog  displacement  area is also  fold  attributed  to to  phase of  that outer  folding.  could conceivably  coalfield,  the  the  have  formation  of  the  large  arc  extension  scale during  of  high the  second phase of deformation (Moffat and Bustin, 1984).  3.3 DTSCIISSTON The  exposure  of the Toodoggone  Lake Group sediments of  a  structural  on  the  buckle  rock folds  perpendicular dome-like  in the core of the  interference  sequence by to  a the  anticline  volcanics below the overlying Spatsizi and Bowser  pattern  in  the  resulting  area.  In  second  phase  original  folds  in the  doubly plunging anticline may be an  to  phase anticline. The  of  the  Type  I  interference  pattern  to  have  thesis map  pattern  area.  developed  of Ramsay  to  first  phase  trending  the  folds  upright  approximately  development  This dome probably  of  the  represents  dome  the  i n Spatsizi is geometrically  (1967), although  fault  high point of  led  folds  two sets of  superposition of a second phase anticline on a  than  the  of  overprinting of  buckle  applies to folds formed by simple shear rather that cuts through  superposition  the  upright  seems  centre of the  interference  the  Spatsizi,  a structural culmination resulting from the first  from  expression  Ramsay's  buckling. The i n the  large  thesis map  formed as a result of high tensions present at the apices of such  Type scale  I  pattern  high-angle  area may  structures.  similar  have  4. BIQCHRQNQLQGY  4.1 T N T R O D I J C T I O N : Z O N A L S C H E M E S Of  all fossil organisms  have provided geologists known. The rich  Jurassic  concept  ammonite  ammonite  culminating European  in  faunas  led  standard by  European  standard  (1961, p. 438) world  " . . .  from  the  of  a means  is  and Great  of  known as  the  development  of  increasingly  Liassic  ammonite  zones  et  standards  al.  of  the  creation  standard  northwest  refined  subzones  ammonite ' distribution, of  standard  the  northwest  cannot  be  zonal  of  application  European  of many  ranges  of  of zonal tables unique to  the  of correlating between  time  served  the  of  the  ammonite different  as  of  a  schemes northwest  the  province.  directly applied to  absence or rarity  relative  has  European  the  of the  This  the  application  zonal work in other parts of the world. However, due to Jurassic  (1961).  and  subsequent  the  of  the  account  Britain. The  be  limited outside  question  provinces.". The  ammonites  frame  Early  state that on  and Cretaceous  to  to  Dean  reference to all subsequent nature  of Germany  throughout what has come  the  provincial  Jurassic  with one of the most detailed and easily utilized zonal  province  province  used i n biostratigraphy,  PROVTNCIALTTY  of biostratigraphy itself was, i n large part, developed i n light o f  of these early ideas Liassic  AND AMMONITE  other index  Dean  et  al.  parts  of  the  species,  species  in  ammonite  northwest  apart  (different)  provinces,  the different provinces is an area of active research.  the problem that shall be addressed i n this chapter  with specific reference to the  and It is  Spatsizi  fauna. The  restriction  on  the  application  particular importance  i n view of the  distinct realms.  Lower Jurassic,  by  two  The  dominant  European  province  European  Alpine  faunal was belt  of  division and  realms;  the  a  part,  and  and  areas  to  the  northwest  of Early Jurassic  particularily the northern  the the  Boreal  southern south  54  and  European  standard  ammonite  distribution into  Pliensbachian, realm,  Tethyan southeast  of  was  which  realm  that  (Donovan,  is  of  characterized the  northwest  included 1967;  the  Hallam,  55  1969;  Howarth,  parallel  to  1973b;  latitude  fig.  and  5.1).  is  The  marked  boundary  by  a  between  narrow  zone  the  of  two  overlap  realms  was  running  through  European Mediterranean region. The origin and nature of these faunal realms in the following chapter on Because the Early  Jurassic,  zonal  is  the  discussed  paleobiogeography.  two realms  the  roughly  were  standard  occupied by significantly different derived  from  successions  in  the  faunas  during the  northwest  European  province (of the Boreal realm) cannot be directly applied to the Tethyan realm, that is, a zonal  standard pertaining to the  of the  Tethyan  and subzones  Lias have  Tethyan  been  achieved  zone,  where  through studies zonal  index  faunas  of the  fossils  ZONATTON OF NORTH Lower  been  northwest Tethyan 1968;  Jurassic  analyzed with  workers have  come  between  of  both  seen  elements North  respect to  derivation, in  Howarth, 1973b; European  question, and the of the America.  AMERICAN  stratigraphic  data  the  realms  of  Liassic  zones  Europe  from  Smith, 1981,  zonal  need western Based  standard  has  arisen  North on  that  can  Boreal and Tethyan realms  western  the  North  found  narrow overlap  together.  same  Tipper, entire  America  standard.  western  in  western  western  traditionally  recently,  a  Boreal,  North result,  North  American fauna and associated of  Tethyan  aspect  however,  mixed,  America  American  forms  collected  (Imlay,  fauna  endemic from  to  of and  application of  for a revised zonal scheme pertaining to the  ammonites  Further  American faunas are  into  1981). A s a  have  More  North  division  distinguished  1983; to  been  i n the  of pandemic distribution.  European  the  be  have  fauna  has  FAUNAS  northwest  and  the  mixed Boreal/Tethyan  to realize that not all of the  European fauna  northwest  standard  parts  for the Tethyan realm has not yet been compiled.  evidence of correlation is provided by ammonites  4.2  Zonal schemes for  proposed, but a comprehensive  Correlation of contemporaneous been  realm itself is needed.  is  the in  Tethyan western  Oregon  and  Nevada, Smith (1981) has proposed a zonal scheme for the m i d Lower Sinemurian to the  56  Lower Toarcian need  to  assigned been  be  (fig. 4.1).  made  to  to  this  Dayiceras  placed  into  (Dommergues  In view of subsequent zonal  scheme.  dayiceroides  the  new  Firstly, North  (Frebold,  genus  taxonomic and zonal work, two changes  1970;  Smith,  Dubariceras,  et al., 1984). Thus, the  and  Dayiceras  American 1981,  the  specimens  1983;  species  Imlay,  following  propinquum  section  Zone  has  considered to represent et al.,  in prep).  the  genus  top  of  In  the  first  Pliensbachian/Toarcian the  been  renamed  northwest  the  to  dayiceroides Zone is now the  boundary,  as  propinquum  the  Lioceratoides  freboldi  Dubariceras  propinquum  Pliensbachian/Toarcian  have  the  and i n  Tiltoniceras  Zone,  and  is  the uppermost Pliensbachian rather than the lowest Toarcian (Smith the  species propinquum  which i n northwest  Tenuicostatum  found below  to  on  short,  Tiltoniceras,  the  (4.4)  1981)  renamed  freboldi Zone. Secondly, as explained i n the discussion of Lioceratoides the  previously  In  western  appearance  of  Dactylioceras,  European  The  L.  Spinatum  longer  considered  Europe (and possibly Siberia)  Zone.  boundary.  is no  North  occurs  America, Lioceratoides  Zone  although  is probably  precise  belong  to  near  the  propinquum  which is here considered  propinquum Zone,  to  to mark  roughly  correlation  with  is the  equivalent European  zonal standards will require further work.  4.3  Z O N A T T O N O F T H E SPATSIZI FAT I N A The  Boreal the  Spatsizi fauna is considered  elements,  thesis  paricularly the  map  area.  map  area  Souther,  (104  I;  thesis  Spatsizi  considered  to  fauna,  on northern Stikinia, including the  Telegraph  be  a  mixed  mainly Tethyan  Boreal/Tethyan  Creek  (94  fig.  in  were not found in  map area  M c C o n n e l l Creek  comprising  found  Amaltheus,  affintiy, although  is  L ) map areas (Tipper and Richards, 1976; the  of mixed Tethyan/Boreal  however,  Tipper, 1978), the  1972), and in the  be  Upper Pliensbachian genus  Amaltheus,  from areas surrounding the  to  biogeographically  map area  (104  D ) , Hazelton (93  1.3; and  fauna.  see  absence  Cry Lake  M ) , and Smithers  forms of  faunas  Frebold,  also Chapter 5, section  unrestricted The  G;  related  is,  by  Amaltheus  5.2).  1964; (93 Thus  association, from  the  NORTHWEST EUROPEAN ZONES ( D e a n at al., 1061)  WESTERN NORTH AMERICAN ZONES (Smith. 1 9 8 1 )  DOMMANTLY BOREAL  DOMINANTLY TETHYAN  or  EAST  UNRESTRICTED  PACIFIC  TOARCIAN Z < cr  Z <  Pleuroceras  Lloceratoides  SPINATUM  PROPINQUUM  Amaltheus  Fannlnoceras  UJ  O D  MARGARITATUS  o <  CD CO  z LU  " I  FANNINI  II  Prodactylioceras DAVOEI  Z < X  rr <  Oubarlceras FREBOLDI  Tragophylloceras IBEX  Luningiceras  Uptonia JAMESONI  PINNAFORME  SINEMURIAN  FIGURE  4.1  Range chari including all the species of the Spatsizi fauna. Both the standard of northwest European zones and the western North American zonal scheme of Smith (1981) are shown, along with the paleobiogeographic affintiy of each faunal elemenL  58  Spatsizi  fauna may be explained by the fact that, while i n Europe  throughout range  the Upper  i n the Upper  comm., break  Pliensbachian, Pliensbachian  it appears  to have  of western  British  1985). Collection failure, poor preservation i n the  Amaltheus  Upper  Pliensbachian  may account  shales  in  a  Amaltheus  much  narrower  stratigraphic  Columbia ( H . W . Tipper,  potential, and/or  the  is present  thesis  a slight  map area  at  pers.  stratigraphic  the  level  of  for its absence.  Correlation of the Spatsizi fauna to both the northwest European standard and to the  scheme  proposed by Smith (1981) has been  the  Spatsizi species  made  where possible. The ranges  are summarized in fig. 4.1. Because  freboldi is found i n such great abundance  the zone  i n the Spatsizi sections,  ammonite its range  in this study as a reference with which to compare the occurrence  of all  Dubariceras  is often used  of many o f the other  Early Pliensbachian species. Observations  on the stratigraphic  ranges  o f certain  genera  i n the Spatsizi  fauna  indicate that the northwest European standard can, i n general aspect, be applied to Boreal elements  of the western  North  American faunas.  However, the details  of the northwest  European standard have become "out of focus' over the distance between northwest Europe and Spatsizi. A s a case i n point, the ranges  o f the Spatsizi representatives  Acanthopleuroceras,  are compared  Tropidoceras,  Europe. In Spatsizi, Uptonia level  Uptonia  sp. ranges the  last  sp. is above  up to about occurrence  Jamesoni to Middle  of  and Uptonia  sp. first appears the last occurrence  i n association  sp.. This  with  ranges  i n northwest  Tropidoceras  sp.. A t this  of Acanthopleuoceras  the middle of the range Tropidoceras  to their  of Dubariceras  range  roughly  cf. A. stahli. freboldi  corresponds  Ibex Zones of northwest Europe. The genus  of the genera  Uptonia,  which  Uptonia is above  to the Upper however, is not  found i n strata above the Jamesoni Zone i n northwest Europe, i.e., it is found below the range  of both  Acanthopleuroceras  and Tropidoceras.  higher i n the sequence i n Spatsizi than do other  The fact  species  that  o f Uptonia  Uptonia  sp. ranges  i n northwest Europe  is consistent with von Hillebrandt's (1981a) observation that Uptonia persisted into the Ibex  59  Zone i n the Tethyan realm. The reason for this extended range i n Tethys may be related to the generally than  more  was present  stable environment that  was prevalent  i n the shallower, epicontinental  i n the deeper  Tethys  ocean  seas o f northwest Europe (Ziegler, 1981;  Hallam, 1971).  4.4  T H E PLIENSBACHIAN/TOARCIAN The  sections  stratigraphic  is not readily  position  BOUNDARY  of the Pliensbachian/Toarcian  apparent  due to the scarcity  of fossils  boundary at this  i n the  Spatsizi  level. F r o m the  faunal information available from Spatsizi, and from work in more fossiliferous sections on the  Queen  appropriate  Charlotte to  Dactylioceras,  Islands  place  the  as suggested  (see  discussion  of  Pliensbachian/Toarcian by Dean  Lioceratoides  boundary  et al. (1961)  at  propinquum), the  first  for the northwest  it  seems  appearance  European  of  Province.  M o r e recently, however, Howarth (1973a) has divided the lowermost zone of the Toarcian, the  Tenuicostatum  subzone  proposed  Toarcian  due to  Zone, into four subzones  by Howarth, the Protogrammoceras the  occurrence  however, the P. paltum  subzone  lower limit of Dactylioceras of  Protogrammoceras  Upper 6).  suggestion been  of  rare  paltum  Dactylioceras  is not recognizable  section  based  i n Yorkshire. The lowest  Subzone,  within  the  was placed subzone.  on available  field  In  i n the Spatsizi  data, so the  is used as the stage boundary i n this study and occurrences  paltum,  Pliensbachian  This approach  at its type  (see also  together  with  Lioceratoides  propinquum,  the description o f P. paltum  to delimiting the Pliensbachian/Toarcian  are  considered  and L. propinquum,  as  Chapter  boundary is i n keeping with  a  made by Howarth (written communication to H . W . Tipper, 1984), and has also  adopted by H a l l  and Howarth (1983) for Arctic Canada, by Smith  for western North America, and by Braga et al. (1982) for southern Spain.  et al., in prep.  5. P A L E O B I O G F . O G R A P H Y  5.1 A M M O N I T E P R O V I N C I A L I T Y The southern  division  Tethyan  of  realm  (1883). The  boundaries  general,  Boreal  the  northern area  has of  Japan  ammonite  been  recognized  Boreal  can  be  defined as  extending  as  far  and eastern  WORLD  distributions  the  realm  hemisphere,  between  Jurassic  TN T H E O T P  and  since  the  Tethyan  south  into  a  pioneering  realms  the  Alpine  Siberia i n Eurasia. The  the  belts  Tethyan  Boreal  work  of  with  time  fluctuated  having occupied as  northern  and  Neumayr but,  in  of  the  northern part of  a  Europe, and  to  an  realm comprised all the  areas to the south of the Boreal realm. Analysis Donovan  the  fauna  towards  Early  Jurassic  the  During  (Hallam,  end  Tethyan  workers (Hallam, 1969;  the  of  1969).  Hettangian  was  fauna  at  After  Sinemurian, there  was  and Boreal realms.  distribution  ammonites  and  at  a  the  an  the  almost  of  total  A t this time the  minimum  for  the  became largely extinct, the  segregation  Jurassic.  genera.  dominated by the the Late  ammonite  the  however,  both  Boreal  Boreal  and  Late  of  In  shown  the  Sinemurian  the  Boreal  ammonites  until,  genera  earliest  Pliensbachian  the  during  the  into  the  ammonites  were greatly  ammonites Tethyan  found  of  Toarcian  unrestricted time,  genera  are  60  the  Tethyan  abundant  in  the  region, a  the  diminished, and the  Boreal  occupied the Tethys' sea. in  that  by an impoverished  first  the  by  to  realm  families Amaltheidae and Liparoceratidae, while to the  families Hildoceratidae and Dactylioceratidae Pliensbachian  the  of ammonite  entire area was populated by pandemic ammonite during  of  provincialism increased  faunas  (1967) showed that  family level  had begun close  part  of  Tethyan  Donovan  the  fauna but rather  number  Early  faunas  least  establishment  degree  at  Howarth, 1973b) has  (or provinciality) of contemporaneous  Lias.  Pliensbachian,  Boreal  distribution of  realm was not occupied by a distinct Boreal  Tethyan  Late  separation  of  Boreal  the  (1967) and subsequent  geographic middle  of  narrow  was south  Only rarely and zone  are  vice  versa;  of  overlap  61  between the  the two realms  that  runs approximately  east-west through  Europe just north of  Mediterranean (fig. 5.1). Neumayr (1883) first recognized this overlap zone and Geczy  (1984) argues that this zone should be considered as a separate realm called Neumayria. Neumayr also recognized that the boundary between the faunal realms was oriented parallel to latitude and concluded that to climatic factors.  could  differentiation between  wide temperature n o t A s Hallam  i n ammonite  distribution; whereas  fluctuations and generally (1969,  1972)  pointed  climatic equability such that temperature  variations between  of the condition of the Jurassic  distribution  exhibits  a  near  the  was due  temperature  the Boreal  lower temperatures,  out, however,  were less pronounced than would be observed Evidence  the realms  Donovan (1967) and Howarth (1973) concluded that water  was the main controlling factor tolerate  faunal  forms could  the Tethyan  Jurassic  was a  forms  time  the Boreal and Tehyan  realms  today over the equivalent span of latitude.  climate  is twofold;  w o r l d - w i d e uniformity  (Hallam,  firstly, 1969)  Jurassic  land plant  and second,  because  none of the continents  occupied the polar regions during the Jurassic, polar ice caps  unable  any great  extent  (Sellwood,  and Boreal  realms  of the Early Jurassic  to  between  develop  to  the Tethyan  temperature  differences  between  As  an  postulated the  alternative  that the Boreal  addition of river  (1972, p. 403) later of  to  1978).  the  temperature  control  to  abandoned  salinity i n the northern  a  partly  epicontinental  stating  sea being  were  differences  be comparable  to  areas of modern oceans regions.  distribution,  Hallam  (1969)  to lower salinity levels caused by  land-locked,  this hypothesis,  on  temperature  would  modern day tropical and boreal  realm originated i n response  water  Thus,  the tropical and warm temperate  (Reid, 1973), rather than between  of  epicontinental that  kept  " . . . more  Boreal  sea.  Hallam  it is hard to conceive or less constant  for a  period sufficiently long to allow a boreal fauna to develop, at a level only slightly below that  of  normal  ocean  water,  brachiopods, and echinoderms hypotheses,  Hallam  (1972)  thereby  allowing  stenohaline  to survive.". In rejecting  and also  Reid  (1973)  groups  such  as  the simple temperature  adopted  the  view  that  ammonites, and salinity  the principal  62  FIGURE  5.1  Tethyan and Boreal distribution of the Late Pliensbachian ammonite families Amaltheidae and Hildoceratidae (modified from Donovan, 1967).  63  controlling stability,  factor  as proposed  marine  diversity  stability-time Boreal  Sea  fluctuations  Boreal/Tethyan by Saunders  invertebrates.  species  the  in  decreases  hypothesis  occupied  as  to  have  stability  or  shallow,  of  environmental  o f modern  predictibility  epeiric  sea  benthic  hypothesis,  decreases.  The  situation as follows. The subject  including salinity, temperature,  effects o f even higher  a  that  stability, or stability-time  applied to the Early Jurassic been  parameters  was  for the distribution control  environmental  has been  is thought i n several  sea  (1969)  differentiation  According to the environmental  potentially drastic  Boreal  faunal  to  relatively  wide  and turbidity, apart  from  minor changes i n sea level. Moreover, because the  paleo-latitudes  than  the  Tethys,  the  effects  of  seasonality  would have been more marked. Only a low diversity, eurytopic fauna was able to develop over  time  by contrast,  was a deeper,  more  stable marine setting i n which evolved a high diversity of stenotopic  organisms over  time.  Howarth genera  i n this  high-stress  (1973) reports restricted  environment  The Tethys,  that during the Late Pliensbachian there were only five  to the Boreal  realm. N o pandemic genera  realm  as compared  Early  Jurassic  ammonite  faunas  AMERICA: of  differentiation into Boreal, mixed, and Tethyan noted  that  some  of  the  genera  he  faunas  described  from  the Late Pliensbachian genera  more  Mediterranean  in  the  described  a Pliensbachian/Toarcian  being  distinctly  of  distribution  of  Hildoceratidae  Late  Tethyan  region  fauna  aspect,  Pliensbachian  and Dactylioceratidae),  and South America.  i n the  Tethyan  than  from  America  northwestern Arieticeras  i n the  show  faunas  British  the  same  Columbia and  and Leptaleoceras)  Boreal  Oregon  (1973)  (abundant  and mixed  North  as seen i n Europe. Frebold (1964)  eastern  and Howarth Boreal  T H E SPATSTZT F A U N A  western  southern Y u k o n (namely common  14 genera  were living at that time (Howarth, 1973b).  5.2 P R O V I N C I A L I T Y I N W E S T E R N N O R T H The  to about  ammonite  region.  Imlay  and western  outlined  o f both  detail  Tethyan  western  (1968)  California as  i n further  Amaltheidae),  were  North  the  (abundant America  64  Taylor et al. (1985) have divided the Boreal,  Tethyan,  characterized to the of  Eastern  Pacific  faunal  of western North America into  realms.  The  Eastern  Pacific  Pacific region. The  ammonite  characteristic  of  genus the  Fanninoceras,  Eastern  mentioned forms with  bivalve genera  the  and  Pacific  exception  realm. of  Weyla  and Plicatostylus,  the  ammonite  The  Spatsizi  Plicatostylus  which  Dubariceras fauna  species  freboldi  is restricted  all  is  endemic  all the  contains  the  realm  by a fauna of Tethyan or mixed aspect containing certain elements  eastern  the  and  Jurassic  are  all  the  above  in western  North  America to the conterminous United States. The North of  relatively simple picture of a north to south faunal differentiation in western  America has been recognized as having been  the  various  Cordillera  microplates  (see  also  part, by major Tipper  (1981)  make  1,  section  chapter  that  terranes  the  Boreal/Tethyan  containing  boundary on  displaced farthest  1.4).  Stikinia (on  (fig.  5.2a).  Estimates  km,  and  500  km,  the  Lower  Cordillera apparent  the  which of the  for  Jurassic  faunas  of  the  appears trend  Each  and  of  portion  the  which  craton.  the  lower  to be  Spatsizi  fauna  Fernie  the  oriented  American least  terranes  of  the  Jurassic  occurred.  three  rocks  in  major  (Wrangellia,  to the position of the appears  to  have  been  of  and  the  still  terranes  less on Quesnellia are  respectively were  2500 k m , (Taylor  1800  et  al.,  deposited i n  the  to the craton. As a result of the northward  post-Pliensbachian of the  the  each  Basin and Sonomia  northwest-southeast  into Boreal latitudes. If each  North  (Wrangellia), somewhat less farther  Quesnellia,  Boreal/Tethyan  from  movement  is bound, at  of  boundary  is located),  northward displacement  rocks of the  simply results  on  Middle  Moreover, the  the  terranes  movement  boundary  Wrangellia, Stikinia, and  terranes,  of  displaced northward with respect  same position they now occupy with respect displacement  western  northward on the westernmost terrane  on  1984). Only  the  Boreal/Tethyan  Stikinia, and Quesnellia) has been  north  up  dextral strike-slip faults along showed  allochthonous  that  greatly complicated by the  terranes  boundary (see  in  the  western  Canadian  line A - A ' in fig. 5.2a).  northward displacement is examined  separately  This  of  Tethyan  the  expected  65  north  to south  transition  is observed  original latitudes, their respective  i n each,  Boreal/Tethyan  and i f the terranes are restored boundaries  to their  would l i n e - u p roughly parallel  to latitude as they should (line B - B ' , fig. 5.2b). The contains half  fauna  is considered  elements o f the Eastern  o f the Stikine  Quesnellia gives  Spatsizi  affinity  biogeographically  concerning  Pacific realm. Faunas  as well  are o f the same affinity  the  affinities  Terrane,  of  all  related  the  faunas  to be o f mixed Boreal/Tethyan  as from  collected  smaller  as the Spatsizi  from the entire  areas o n northern fauna  Pliensbachian  ammonite  of northwestern  North  of the Spatsizi fauna provides further  genera America.  of  displacement  the  The  northern  Wrangellia and  (fig. 5.2a). Table  support to the already  the origin, nature, and subsequent tectonic  affinity and also  5.1, below, Spatsizi  and  paleobiogeographic established  theories  o f Pliensbachian  faunas  in western North America as outlined above.  GENUS Acanthopleuroceras (Amaltheus) (Apoderoceras) Arieticeras Aveyroniceras Dayiceras Dubariceras freboldi Fanninoceras (Fontanelliceras) Leptaleoceras Lioceratoides  TETHYAN  BOREAL  EAST PACIFIC  UNRESTRICTED *  •  •  • •  (Liparoceras (Becheiceras)) Luningiceras Metaderoceras Protogrammoceras Reynesocoeloceras Tropidoceras Uptonia  Table 5.1: List o f genera comprising the mixed-Eastern Pacific fauna o f the Spatsizi and biogeographically related areas. Genera i n parentheses are elements o f the overall northwestern North American mixed fauna but were not found i n the thesis area. In addition to the information provided i n this study, faunal information was taken from Frebold (1964, 1970), Frebold and Tipper (1970), Tipper and Richards (1976), Tipper (1978), and Imlay (1981).  66  FIGURE  5.2a  D i a g r a m a i i c illustration o f the relative present day positions o f the three major a l l o c h i h o n o u s terranes containing L o w e r Jurassic rocks w i t h respect to the stable c r a i o n . L i n e A - A ' shows the a p p r o x i m a t e trend o f the Tethyan/Boreal b o u n d a r y as it now appears ( m o d i f i e d f r o m S m i t h and T i p p e r , in press).  67  FIGURE  5.2b  D i a g r a m a i i c i l l u s i r a i i o n o f the a p p r o x i m a t e positions o f the three major a l l o c h t h o n o u s icrranes c o n t a i n i n g L o w e r Jurassic rocks w i t h respect to the stable cra;on prior to p o s t - P l i e n s b a c h i a n n o r t h w a r d transporL L i n e B - E f shows the a p p r o x i m a t e trend o f the T e t h y a n / B o r e a l b o u n d a r y p r i o r to n o r t h w a r d m o v e m e n t ( m o d i f i e d from S m i t h and T i p p e r , in press).  68  5.3 O L D T O N E W W O R L D M I G R A T I O N R O U T E S Up and  to this point i n the  South  faunas  America (eastern  Pacific  region)  of Eurasia and Africa, but the  to populate the The  discussion, Boreal  question  v  and Tethyan  have  been  question as  an  important  one  because  its  equated  to  of western  North  Boreal  and  World'  faunas  to how the *01d  N e w World* (and i n some instances,  is  faunas  Tethyan came  vice versa) has not been considered.  answer(s)  bears  directly  on  the  as  yet  poorly understood period of initial breakup of the Pangaea supercontinent during the Early Jurassic, and on the tectonic evolution of the western Cordillera. The Jurassic into mode  question is primarily one  of migration routes -  organisms make their way from the Tethys  the  eastern  Pacific region?  of migration) of the  To  answer  ammonites,  the  by which  route(s) did Early  and northwest European (Boreal)  this question  the  life  mode  Early Jurassic  configuration of the  seas  (particularly  the  continents,  and the physical and geological nature of the migration routes need be considered. Ammonites have  had  a  were  originally thought  to  have  world-wide distribution. Although  been  some  free nektonic  forms  organisms  did achieve  and  near w o r l d - w i d e  distribution, it became apparent with the discovery of ammonite provinciality that  ammonite  distribution was constrained by their mode of life, and in some cases their occurrence restricted to particular facies (Hallam, 1969,  1971;  Ziegler 1980). W h i l e the  ammonite populations as a whole was controlled by factors hypothesis, water  the  depth,  (1976) most  mode food,  of life of the substrate,  ammonites  were  fairly shallow water, either  etc.  plankton feeders,  more  planktonic or nektonic  According to  generally  swimming slowly near  were limited), or as benthos. Some a  1980).  the  was  distribution of  explained by the stability-time  individuals controlled where (Zeigler,  to  living  they  lived  Kennedy  close  to  the  in terms and  of  Cobban  substrate  in  bottom (their powers of locomotion  groups, particularity the Phylloceratids, were adapted to  life-habit in areas close  deep shelf or shelf edge (Callomon, 1985;  to the  open  Kennedy and Cobban, 1976).  ocean  such as  the  69  Ammonite  fossils  from pelagic  deposits  are  rare,  and  where  they  do occur,  the  fauna is usually made up of juveniles. This may be attributed to the fact that ammonites had  a  pelagic  larval  as  the  adults,  is  Eventually, and  450  given  stage and that juveniles  case  the juvenile km  by  for  ammonites  away, where  Kennedy  many  and  they  modern began  spent  Cobban,  may  have  lived  cephalopods  their journey  farther  (Kennedy to  the  1976).  Those  individuals  and  inner  their adult life (distances that  offshore  than  Cobban,  1976).  between  150  approximated from  data  died  shelf,  the  as  juveniles  would  have sunk to the pelagic sediments below. The length of the ammonites' larval stage is, of course, unknown, but it does not seem unreasonable invertebrates  to look at the length of the planktonic larval stage i n modern marine  (particularly other molluscs) i n order to gain some  Thorson  (1961) summarized the  relationship between  of  benthic  (9%  195  marine  species  and  19%  of  the  insight into the problem.  length of the pelagic larval  which  represents  the  life  gastropods  and  bivalves, respectively) to the speed of larval transport by ocean currents. Only 5.5% of all the  larval  species  studied by Thorson were  than 3 months and can thus be Thorson (1961, p. 461)  " . . .  found to remain i n  the  plankton for  more  considered true long-distance larvae, which, according to  have to be considered as the chief objects of  transoceanic  transport". O f the species examined, none of the bivalves or gastropods has long-distance larvae. A l l this is not to say that  none of the  it  than  would  had  seem  unlikely  long-distance  problem  larvae.  more  This  5-10%  hypothesis  is  of  all the  worth  had long-distance larvae, but ammonite  consideration  species could have  when  addressing  o f O l d W o r l d to New W o r l d migration of Early Jurassic ammonites (apart  Early Jurassic average  that  ammonites  bivalves and gastropods). If, as Thorson (1961, p. 469)  conditions- even most long-distance  survive the  critical distances across the  Island). . .",  how could short-  even  distances  greater  between  larvae have  eastern  a  much-too-short  pelagic life  Pacific (i.e., from Galapagos  O l d and N e w Worlds via the  from  puts it ". . . under  ocean  of  to  to Christmas  or even long-distance ammonite larvae have survived the  the  the  Panthalassa?  70  (fig.  5.3).  It  is  clear  that  currents must take place  ammonite  migration by  either between  continents  means  of  separated  larval  transport  in  ocean  by a relatively narrow deep  ocean passage, or along the margins of continents, probably not more than about 450  km  from the strandline. In  view  of  probably  did not  close  to  continental  Early  Jurassic  take  restrictions  place  shelves,  O l d to  Early Jurassic rifting  the  across of  outlined  above,  significant spans  namely  of open ocean  through narrow seaways  New World  migration routes  the continents were still coalesced  that  between  may now be  ammonite  migration  but rather  along or  continents,  the  possible  considered. During  into the supercontinent Pangaea, although  of that great landmass had begun in the  Late Triassic (Pindell,  1985). G i v e n  the ammonites were able to migrate along continental margins, two obvious routes the and  Tethys sea and the one  routes  along the  are  easily  documented  eastern Pacific region present themselves,  southern explained  continental transient  margin of since  shelves  presenting  the  Especially  during  periods  organisms  whose  distribution  of  high was  involve  Pangaea.  Early Jurassic of  Pangaea  they  (routes the  A and simple  However,  organisms  with  provinciality (for controlled  the  by  a  B,  wide span  factors  fig.  suffer  example,  5.3). along  the of  the  related  between  one along the northern  migration  they  that  two  the  well  drawback  latitude to  Late  to  These  of  cross.  Pliensbachian),  latitude  would  be  Jurassic  an  prevented from migrating along these routes. It  is  epicontinental  fairly  well  seaway  accepted  between  that  Greenland  there and  existed  during  Scandinavia,  the  Early  connecting  the  northwest  European Boreal sea with the arctic regions of North America and Eurasia (fig. 5.3, route C; Old  Howarth,  1973b;  to N e w W o r l d  Hallam,  1977). Boreal ammonites could have  moved freely  from  by way of this seaway, but the Tethyan ammonites would not  the have  been able to migrate along this route due to its high latitude position. Two between  other  east Africa  routes  of  a  more  conjectural  nature  and Antarctica, around Cape H o r n  remain;  one  and up the  through  a  west coast of  seaway South  71  FIGURE  5.3  Early  Jurassic  Pliensbachian Hallam.  1977).  continental migration  reconstruction routes  (modified  of  Pangaea  from  showing  Briden  et  the  possible  al. (1974),  and  72  America;  the  other  through  Hispanic Corridor of require the  Smith (1983;  migration through  supercontinent,  evidence.  As  the  Hallam  necessarily  require  and  ephemeral,  often  the  some  a seaway  central  routes  D  portion of  existence (1977)  early  of  and  floored by  epicontinental  and  proto-Caribbean  and E, fig. 5.3). Pangaea,  these  Smith  Atlantic  rather  seaways (1983)  true  calls  have  oceanic  seas. Evidence  Because both  than for  around  close  pointed  such  out,  and thus their existence is not,  well  the  documented.  hypothesis  that  distribution  in  The  weight  Early  Jurassic  the  eastern  of  evidence  (particularily  Pacific  region  data  that  the Early Bajocian. to have been central  indicates Hallam  the  more  Middle  the  available  migrated  central  from  may  have  establishment  existed,  does  not  seaways  is  to  the  always  favour  faunas  not,  of  the  Tethyan Pacific  (1977) summarizes the lower Middle  Jurassic  the  at  was established  east African  seaway  least intermittently,  of a permenant  the  eastern  Atlantic seaway  (1977) considered  of  unfortunately,  to  of  along shallow,  appears  Tethys  or  routes  margins  at least by  (route  D , fig.  likely migration route, but also pointed out that an  Atlantic seaway  times, but that  that  occur  Pliensbachian/Toarcian)  region via the Hispanic Corridor. Westermann ammonite  now  the  migration  epicontinental  unfortunately, always well preserved,  these  investigation  crust, but may  of  area,  seaway  as  early  5.3)  epicontinental as  did not occur until the  Sinemurian end of  the  Jurassic. Paleontologic evidence supporting the existence of the central Atlantic seaway during  the  Early  Jurassic  Mancenedo, Stylothalamia (formerly  1979),  paleobiogeographical  Corridor  can  evidence  of  the  the  distribution  dicoelitid  of  belemnites  as  evidence  However, be the  Dayiceras  two  accepted.  dayiceroides that  points  the of  Firstly, as  Corridor in the  area  the  Weyla  1980),  Pliensbachian  the  (Damborenea calcareous  ammonite  genus  and sponge  Dubariceras  by Smith, 1983). Thus, there is fairly good  Hispanic caution Scott  bivalve  (Jeletzky,  (von Hillebrandt, 1981b), and the  described  Sinemurian.  includes  must  (1984)  between  Corridor be  set  points  eastern  existed  as  forth  before  out,  there  is  early the an  Mexico and Morocco;  "as  the  Hispanic  absence Le.,  of  faunal  73  evidence  of  the  Corridor  can  Taylor et al. (1984, p. 124) faunas  " . . .  and eastern the  Pacific via . . . that  imply  the  of  the  during  Tethys  its  postulated  end  points.  Secondly,  the  a direct connection between  the  western  Tethys  Hispanic Corridor of Smith (1983). It merely expresses Early and M i d d l e  extended circum-globally . . . .  as those  found near  explain that the Tethyan affinity of western North American  does not necessarily  observation  genera  only be  Jurassic  the  distribution of  numerous  at about the same comparatively low paleo-latitude  itself. Inference  of a  Hispanic Corridor  can, therefore,  be  made  only i f the taxa i n question are absent i n the eastern Tethys and/or western P a c i f i c " . Geologic  and  tectonic  evidence  of  an  Early  Jurassic  central  Atlantic  seaway  is  tenuous. Sinemurian ammonites found i n the Huayacocotla Basin in eastern  Mexico provide  evidence  of  whether  this  a  marine fauna  (Schmidt-Effing, crustal  blocks  between This  suggests  originated  1980;  Scott,  along  North  and that  influence  several South  the  in from  the the  Gulf  of  eastern  Mexico region  during  that  Pacific  Tethys  is  1985). According  to Pindell  shear  western  zones  in  America between  Sinemurian ammonites  the  or  (1985), southeasterly  Mexico  Late  in the  the  maintained  Triassic  and late  a  time,  but  problematic transport land  Middle  of  bridge Jurassic.  Huayacocotla Basin must have  been  derived from the Tethys, but it also implies that a marine connection between Tethys and the  east  Pacific  could  not  have  been  established  until  post-Callovian times. However,  Pindell's Central American land bridge may only have been intermittently effective. (1985) also presents for  the  Late  paleogeographic  Triassic  and  early  maps of  Middle  the  Gulf  Jurassic.  was underway by Bajocian  times, and the  area are of Callovian age and rest on oceanic a  central  Atlantic  seaway  prior  to  the  Mexico-central Atlantic region  According  attenuation of continental crust and minor seafloor region  of  to  this  spreading i n the  synthesis,  extensive  G u l f - c e n t r a l Atlantic  oldest sedimentary rocks drilled in the  crust (Scott, 1984). Thus, the  Bajocian  Pindell  is  not,  established, but at the same time cannot be ruled o u t  based  on  geologic  existence data,  of  firmly  74  made  The  migration  routes  their  way to  western  exception western  o f those North  faunal  by which North  elements  America, forms  the Spatsizi  America of  can now be  eastern  of different  and biogeographically  Pacific  affinities  northwest  European  and Scandinavia (route southward  upon.  which  were  would permit them;  With  the  endemic  arrived i n western  via the straits  between  C , fig. 5.3). F r o m Arctic North America the Boreal epeiric seas of western  faunas  to  North  are believed to have migrated from  province to the Arctic region  into the Liassic  latitudinal tolerance  affinity  probably  America via different pathways. Boreal faunal elements the  speculated  related  North  Greenland  faunas  America as far south  to a paleolatitude  moved as their  now approximated by the 49th  parallel. Most Tethyan America  ammonites  via the central  (and other  Atlantic seaway  periods of low provinciality such unrestricted  faunas  may have  latitude-transcending Atlantic  ammonite  (1983).  Spatsizi  It follows that  fauna  (including  Reynesocoeloceras  western also  as the Late  migrated  to  (for example,  North  abundant  of that  cf.  R.  age found  western  routes  sp.,  E , fig. 5.3). During  America  and D ,  ammonite  fauna, genera  Leptaleoceras,  fig.  way of  5.3).  The  freboldi,  more central  the most  has been  documented by  of Tethyan  affinity i n the  muticum, and  The migration pattern  the hypothesized  by  Dubariceras  Metaderoceras  Aveyroniceras,  America by the same route. i n Spatsizi, supports  North  A , B,  Pliensbachian  Dayiceras  (route  North  Sinemurian and Early Toarcian, the more  i n the, Spatsizi  the other  incertum,  probably arrived i n western  i n the Pliensbachian  migration o f of the Early Pliensbachian  abundant Smith  routes  organisms)  M.  evdutum,  Arieticeras)  arrived i n  of the bivalve  central-Atlantic  seaway  Weyla,  (Damborenea  and Mancenedo, 1979). Upon southward) members Spatsizi  to  arrival their  in  latitude  of the N o r t h fauna  lived.  the  N e w World, tolerance  limit  American Boreal  Post-Pliensbachian  the  Tethyan  where  faunas.  transport  It  they  forms  spread  mixed  with  was i n this  of the terranes  northward (and the  southernmost  mixing zone  that  on which these  the  faunas  75 were preserved has resulted in their present day distribution in Boreal paleolatitudes.  6. S Y S T E M A T I C P A L F O N T O T . O G Y  6.1 INTRODUCTION The  classification of Pliensbachian ammonites  i n this study largely follows that  Donovan et al. (1981). However, the following exceptions been  to this classification scheme  of  have  made.  1)  The  subfamilies Polymorphitinae (including the genera  Acanthopleuroceratinae  (with  the  Luningiceras)  family  Polymorphitidae  of  classification  the  i n the  Treatise  on  genera  Uptonia  and Dayiceras)  and  Tropidoceras,  and  Acanthopleuroceras,  Invertebrate  are  retained  Paleontology  herein (Part  following  L , Arkell  et  the al.,  1957). 2)  The  genus  Dubariceras  is  assigned  with the work of Dommergues 3)  The to  genus  Reynesocoeloceras  Dactylioceratidae,  to  the  family  Eoderoceratidae  in  accordance  et al. (1984).  is assigned  following the  work  to the of  family Coeloceratidae  Geczy  (1976),  rather  Wiedenmayer  than (1977,  1980), and von Hillebrandt (1981a). It should be  noted here that the preservation  poor. External moulds are moulds and external  the most abundant  casts are  of the Spatsizi material is generally  type of body fossil found, whereas  internal  less common. Original shell material and indications of  the  suture lines are rarely preserved i n the material studied.  6.2 M E A S U R E M E N T S All  A N D ABREVIATIONS  measurements  the measurements  made in this study are  used in the systematic  c  =  circa  D  =  shell  UD  =  umbilical diameter at  in millimetres. The  abbreviations  descriptions are defined as follows:  diameter diameter=D  76  denoting  77  U  =  UD/D x  WH  =  whorl height at  diameter=D  WW  =  whorl width at  diameter=D  PRHW  =  primary  whorl at  6.3  100  ribs  per  half  whorl,  counted  on  the  larger,  or  adoral  half  diameter=D  SYSTEMATIC DESCRIPTIONS Order A M M O N O I D E A Suborder  ZITTEL,  AMMONITINA  1884  HYATT,  Superfamily E O D E R O C E R A T A C E A E Family P O L Y M O R P H I T I D A E  1889  SPATH,  HAUG,  Subfamily P O L Y M O R P H T T I N A E H A U G , Genus Uptonia  TYPE  SPECIES:  original  Ammonites  jamesoni  BUCKMAN,  SOWERBY,  1887 1887  1897  1827  (p.  105,  pi.  555,  fig.  1)  by  designation.  REMARKS:  Shell evolute, whorl section  ellipsoidal to ogival. Umbilical wall  umbilical edge rounded. Ventral shoulder rounded, venter Ornament  varies with  growth. Earliest  they posses a keel and ventro- lateral tubercles. stressed the gives  1929  weak  way to  a  development non-tuberculate  whorls are  similar to  Polymorphites  ?Jamesonites B U C K M A N ,  1923;  i n that  In the original description, Buckman (1898)  by  sinuous ribs that cross the venter to form ventral  SYNONYMS:  inflated.  and brevity of this spinous stage. The stage marked  low, shallow;  strong, prorsiradiate,  early spinous stage straight  to  slightly  chevrons.  Microceras  HYATT,  1867,  non H A L L ,  1845.  78  AGE  AND  DISTRIBUTION:  province  but  is  also  found  southern  Alaska. Uptonia  Uptonia  in  is  the  is  most  abundant  Mediterranean  restricted  to  the  in  region,  the  Mexico,  Jamesoni Zone  in  northwest British  European  Columbia  and  Europe,  but  northwest  persists into the Ibex Zone i n the Mediterranean region (von Hillebrandt, 1981a).  Uptonia  Plate  cf.  1981  Uptonia  1, fig. l a - d ;  sp. B I M L A Y , p. 37, p i . 9,  MATERIAL; Ten specimens fine  sp.  preserved  as  2a-d.  fig.  5-7.  and  internal  external  moulds  in  siltstone  sandstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-90926  25  9.5  38  7  -  20  C-90843(U)  c29  11.5  40  8.5  c3.5  22  midvolute,  whorl  DESCRIPTION:  Shell  section  umbilical edge rounded. Flanks are convex; Ornamentation arise  at  shoulder  the  consists  umbilical  and continue  edge. onto  Alaska assigned conspecific  to  The  Spatsizi  to Uptonia any  venter  bend to  form  rectiradiate sharply  and  sp. B  low,  forward  just  ventral chevrons.  Uptonia  sp.  are  shallow; venter.  slightly sinuous below  ribs  the  A t diameters  to be marked by small ventro-lateral  of  wall  ventral shoulder rounds onto inflated  simple  ribs  specimens  previously  their identification as such.  strong,  The  the  about 8 mm, the ribs appear  DISCUSSION:  of  ellipsoidal. Umbilical  that  ventral  less  than  tubercles.  similar  to  specimens  from  by Imlay (1981). If the Spatsizi and Alaskan material is  defined  species  of  Uptonia,  their  small  size  has  prevented  79  OCCURRENCE:  In Spatsizi,  Uptonia  sp.  first  appears  Dubariceras freboldi. A t this level it is associated A  discussion  of  the  Acanthopleuroceras As specimen  relative  of  the  the base  Dayiceras  genera  o f the range  mentioned  above,  of Dubariceras  sp. and Tropidoceras sp..  Uptonia,  Tropidoceras,  the Spatsizi  specimens  to Uptonia  freboldi  of  Uptonia  sp. B by Imalay  from Alaska, however,  (1981). Imlay  Uptonia  also  to a  reported  sp. B and D. freboldi their ranges  is uncertain. In the Queen Charlotte Islands, a single specimen similar to Uptonia found i n association with Dubariceras freboldi ( H . W . Tipper, pers. comm.,  AGE;  and  sp. are similar  were not found at the same locality i n Alaska so that the relation between  Localities:  of  i n Spatsizi and northwest Europe is given i n Chapter 4 (Biochronology).  from Alaska assigned  specimens  ranges  with  near  sp. was  1985).  64, 139.  Early Pliensbachian (D. freboldi Zone).  Genus Dayiceras  TYPE  SPECIES:  original  Dayiceras  pdymorphoides  S P A T H , 1920  SPATH,  1920 (p. 541, p i . 15, fig. 1-4), by  designation.  REMARKS:  Shell midvolute, whorl section  ellipsoidal to ogival. Ornament consists  of fine,  dense, sinuous ribs that are prorsiradiate on the umbilical wall, sinuous on the flanks, and terminate  on the ventral  median row of tubercles  AGE but  shoulder  (Smith,  1981).  elongate  tubercles.  The venter  which commonly coalesce to form a crenulate  A N D DTSTRIBimON: has not been  in radially  reported  It has been  Dayiceras from  is found in the Ibex Zone  any other  reported  from  part  a  keel.  of southern  England  European  Province  of the northwest  the Ibex Zone  bears  o f Portugal  (Mouterde, 1951;  80  Mouterde and Ruget, 1970), North Africa (Rakus, 1977,  1980). This  distribution suggests  that  1972), and northern Italy  Dayiceras  was most  common  (Wiedenmayer, i n the  Tethyan  region but that it was also present i n that portion of the Boreal realm now occupied by Dorset  in southern  England. This view is i n difference  al. (1984) that Dayiceras The  presence  migration  of  northwest  European  that  this  of  allowed Tethyan  held by Dommergues  el  was primarily boreal in distribution. rare  Tethyan areas  to that  Dayiceras  form during  "stragglers'  via the to  in a  southern  marine  England  connection  may between  Early Pliensbachian. The wander  into  the  Boreal  be  the  existance  realm,  due  limited  Tethyan  of  and  to  a  vice  and  connection versa,  has  been suggested by Donovan (1967) and Howarth .(1973b).  Dayiceras sp. Plate 1, fig. 3 a - d ; plate 2, fig. l a - d , 2a, b.  MATERIAL:  Four specimens poorly preserved as internal and external moulds i n siltstone.  MEASUREMENTS: DESCRIPTION:  N o t available due to poor preservation.  Shell evolute to midvolute; whorl section is ogival. Umbilical wall is low,  abrupt; umbilical edge rounded. Flanks are convex;  ventral shoulder abruptly rounded. The  venter is convex, narrow. Ornament where  they  consists  trend  of  dense,  fine  rursiradiately, then  become  foreward near the  ventral shoulder where  The  weakly past  ribs  continue  the  sinuous  flexuous  they  tubercles  onto  venter.  DISCUSSION:  of Dayiceras  Spatsizi specimens  that on  arise the  on  the  flanks  umbilical wall  and  bend  are marked by radially elongate  weakly beaded keel is present on the  The  ribs  the  venter,  but  fade  sp. are similar to  gently  tubercles.  rapidly.  A low,  Dubariceras  freboldi  81 in their form of ribbing and volution, but they differ from  Dub.  freboldi  by their low  median keel, narrower whorl section, and slightly coarser ribbing, the close morphological and  Dub.  stratigraphic association between  freboldi  and  Dayiceras Uptonia  association between the two forms just mentioned with silviesi)  raises questions as to the phylogenetic relationship  creating the genus  Dubariceras,  was derived from  Metaderoceras,  Morphologic convergence family Eoderoceratidae (Uptonia  and  Dayiceras)  Dommergues  et  al.  sp. (as well as the sp. and  Metaderoceras  between these genera. In  (1984) stated that although  Dubariceras  it is morphologically convergent to the Polymorphitids.  could effectively explain the similarity between members of the (Metaderoceras  and  Dubariceras)  and the family Polymorphitidae  found in the Spatsizi collections. Sutural studies of the specimens  would provide the most conclusive evidence of the familial association between these genera in Spatsizi, but their poor preservation has made this impossible.  OCCURRENCE: The specimens of occurrence of  Dayiceras  Dubariceras  freboldi.  of  muticum,  Dayiceras  sp. described here represent the first known Dayiceras  in western North America. It is found  with  Uptonia  but it may range slightly higher than  M.  sp.,  sp. occurs within the range  Metaderoceras  silviesi  and  M.  silviesi.  localities: 62, 64, 87. AGE:  Lower Pliensbachian  (D.  freboldi  Zone).  Subfamily ACANTHOPLEUROCERATINAE ARKELL, 1950 Genus  TYPE SPECIES: 1970).  Ammonites  Acanthopleuroceras  valdani  HYATT, 1900  D'ORBIGNY, 1844, by subsequent designation (Getty,  82  REMARKS: moderately straight,  Shell  evolute  compressed.  simple,  unituberculate  to slightly midvolute;  Venter  rectiradiate  and  Acanthopleuroceras  is angular to  project  and bears  slightly  weakly  whorl  the  differs from Tropidoceras  quadrate  (pentagonal)  a blunt keel. Ornament  rursiradiate  onto  section  ribs.  venter  The from  ribs  may  to  consists be  ventro-lateral  of  bi-  or  tubercles.  by having a generally less compressed  whorl  section, straighter, tuberculate ribs, a less prominant keel, and a lack of secondary ribbing on the ventral surface. The subject  for debate.  represent belong  phylogenetic  relationship  Dommerge  between  and Mouterde  Acanthopleuroceras (1978,  evolution within a single lineage, whereas to separate  numerous exemplified  forms  lineages.  Geczy  intermediate  (1976)  between  by the genetically  draws  1981)  nature  consider  is  the two genera  a to  Wiedenmayer (1977) considers them to attention  Acanthopleuroceras  ambiguous  and Tropidoceras  to the fact  that  and Tropidoceras.  of certain  species,  there  This  including  exist  point is  stahli and  actaeon, which have been assigned to both genera by different workers.  SYNONYMS:  AGE  Cycloceras  HYATT,  1867, non M c C o y , 1884.  A N D D I S T R I B U T I O N : Acanthopleuroceras  is a  cosmopolitan  form  found  i n both  the Boreal and Tethyan realms. It is characteristic of the Ibex Zone and reaches its acme in the middle part of this zone (Geczy, 1976; Hoffmann, 1982; Dean et al., 1961).  Acanthopleuroceras  cf.  A.  stahli ( O P P E L ,  1853)  Plate 2, fig. 3 - 5  •1853 1976  Ammonites  radians  Acanthopleuroceras  nummismalis  OPPEL,  p. 51, p i . 3,  stahli ( O P P E L ) - G E C Z Y ,  fig.  p. 95, p i . 18,  2. fig.  4-6.  83  1977  Tropidoceras  71981  stahli ( O P P E L ) - W I E D E N M A Y E R , p. 65, p i . 14, fig. 3 - 1 1 .  Acanthopleuroceras  sp. S M I T H , p. 256, p i . 10, fig. 9, 10.  Other synonyms, see Wiedenmayer, 1977.  MATERIAL:  Fourteen  external  volcaniclastic sandstone  and internal moulds all preserved i n coarse,  and pebbly  poorly sorted  sandstone.  MEASUREMENTS: SPECIMEN  D  LTD  U  WH  WW  PRHW  C-90930(A)  43  19  44  13  -  17  C-90930(B)  42  19.5  46  13  7  17  DESCRIPTION: low, steep;  Shell evolute, whorl section subquadrate. Umbilicus shallow; umbilical wall  umbilical edge rounded. Flanks convex, ventral shoulder rounded. Venter fairly  broad, fastigate, bearing a blunt keel. Ornament consists of dense, straight, slightly rursiradiate ribs. Ribbing is coarse and bears a single row o f small ventro-lateral  tubercles  from which  the ribs project  slightly  adorally.  DISCUSSION:  The Spatsizi specimens  Geczy  and Wiedenmayer  (1976)  However,  of A. cf. A. stahli are similar to those  (1977)  in  their  whorl  the inner whorls of the Spatsizi specimens  section  are more  and  form  densely  figured of  by  ribbing.  ribbed than  the  illustrated European specimens. The pinnaforme  Spatsizi  material  except that  may be  confused  with  the  inner  whorls  of  A. cf. A. stahli is less evolute (expansion rate about  Luningiceras 1.8-2.0)  the holotype o f L. pinnaforme (expansion rate about 1.5) figured by Smith (1981).  than  84  OCCURRENCE:  is found in both the Northwest European and the Tethyan  A . stahli  faunal realms. It has been reported from England, Germany, France, Italy, and Hungary. The  Spatsizi specimens  of A . cf. stahli  are the first reported  America, although specimens collected by Smith (1981) assigned to Acanthopleuroceras occur  below the range  measured  stratigraphic  from western North  from Oregon and Nevada and  spp. are likely conspecific to the Spatsizi material. They  of Dubariceras  level encountered  freboldi  in Spatsizi and represent  during the course  the lowest  of this study. They were  recovered from rocks directly overlying the highest flow of the Toodoggone volcanics in the thesis map area. Although no other ammonite genera or species are represented at this locality, sediment pods of an equivalent or slightly lower stratigraphic level, found within  the volcanic  Metaderoceras  and  pile,  evolutum  (see  Nevada, M. evolutum  have  yielded collections  containing  section on Metaderoceras  evolutum  is found in the Pinnaforme  A . cf.  A . stahli  with  for location). In Oregon  Zone of Smith (1981), roughly  equivalent to the Jamesoni and lowermost Ibex Zones of the N.W. European Province. In Europe, A . stahli is found in the Ibex Zone. Localities: 70, 137, 138, 141. AGE: Early Pliensbachian ( L . pinnaforme Zone).  Genus Tropidoceras HYATT, 1867  TYPE  SPECIES:  Ammonites  masseanum  D'ORBIGNY,  1844, by subsequent designation  (Haug, 1885, p. 606).  REMARKS: Shell evolute, whorl section compressed, lanceolate to ellipsoidal. Venter bears a distinct, commonly high keel. Ornament consists of straight to sigmoidal, non-tuberculate primary ribs that project onto the venter where they are commonly differentiated into  85  numerous, adorally projecting The the  relationship  generic  Arieticeras,  secondaries.  between  description  of  Leptaleoceras  Tropidoceras  and Acanthopleuroceras  Acanthopleuroceras.  and  Protogrammoceras  The  Upper  are  is  discussed  Pliensbachian  believed  to  have  under  Hildoceratids evolved  from  Tropidoceras.  AGE  A N D DISTRIBUTION:  genus  but is particularly abundant  The  genus  first  appeared  Like  Acanthopleuroceras,  i n the Tethyan  Tropidoceras  is  province (Donovan,  i n the Late Sinemurian and reached  a  cosmopolitan  1967; Smith, 1981).  its acme i n the lower part  of the Ibex Zone.  Tropidoceras  sp.  Plate 3, fig. 2, 3.  MATERIAL:  Three  specimens,  poorly  preserved  as  external  and  internal  moulds  in  siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103304  c48  c27  56  -  -  c20  DESCRIPTION:  Whorl  section  is  ellipsoidal, venter  is narrow  and bears  Umbilical  wall low, fairly steep; umbilical edge rounded. The ribs arise  umbilical  edge,  trend  slightly  ventral shoulder  where  they  secondaries  on the ventral  DISCUSSION:  The  rursiradiately,  fade  then  bend  forward  as  rapidly. The ribs are non-tuberculate  a  high  keel.  on or above the  they  approach  the  and there are no  surface.  fragmentary  nature  of  these  specimens  precludes  confident  specific  86  assignment Frebold  but they  (1970),  do show similarities to specimens  Mouterde  and  Dommergues  of Tropidoceras  (1978),  Dommergues  actaeon figured by  and  Mouterde  (1978),  Imlay (1981), and Smith (1981).  OCCURRENCE: of  the  found  range T.  The of  Spatsizi  Dubariceras  actaeon,  Metaderoceras  specimens of Tropidoceras  to  evolutum  freboldi.  which and  In  the  the  Spatsizi  Dubariceras  Queen  sp. were Charlotte  specimens  are  although  Smith  freboldi,  found just at the Islands,  Frebold  similar, (1981)  base (1970)  associated found  T.  with actaeon  to occur below the range of D. freboldi i n Oregon. Localities: 2, 8. AGE:  Early Pliensbachian (L.  pinnaforme to lower D. freboldi Zone).  Genus Luningiceras  TYPE  SPECIES:  10, fig. 11)  Acanthopleuroceras  SMITH,  (Luningiceras)  pinnaforme  This  genus  was  Acanthopleuroceras.  It  Acanthopleuroceras  and  Acanthopleuroceras.  Luningiceras  includes  created forms  Tropidoceras,  by that  but  Smith  affinities  of  Smith  is here raised to  Luningiceras  reflected i n its assignment  to  to the subfamily  Forms belonging to Luningiceras venter  is  both  fairly broad, convex,  and  1981,  (p.  251,  pi.  ciL)  features  considered generic  rank,  as  a  subgenus  characteristic it  of  of both  more  reminiscent  of  following  a suggestion  by  network of genera, subgenera,  Acanthopleuroceras  and  and so  Tropidoceras  are  whorl sections.  The  Acanthopleuroceratinae.  are  bears a  straight, slightly rursiradiate, and bituberculate  (op.  possess  Dr. Smith, i n order to avoid creating a cumbersome The  SMITH,  by original designation.  REMARKS:  on.  1981  evolute, with subquadrate blunt on the  keel. The outer  ribs are  whorls. The  moderately  dense,  ventral surface  is  87  marked by very dense, strongly projecting In  addition  Acanthopleuroceras valdani,  to  the  type  rursicosta  species,  BUCKMAN  specifically Ammonites  valdani  secondaries. other  forms  and  assigned  certain  specimens  sensu Q U E N S T E D T  to  this  of  genus  include  Acanthopleuroceras  (1884, p i . 35, fig. 4; non fig.  2-5).  AGE  A N D D I S T R I B U T I O N : In Oregon and Nevada, Luningiceras  the range of Dubariceras  freboldi.  occurs i n strata  below  In Europe it is found in rocks of the Ibex Zone from  England and Germany.  Luningiceras  pinnaforme  SMITH,  1981  Plate 3, fig. l a , b.  •1981  Acanthopleuroceras  MATERIAL:  A  single,  large  (Luningiceras)  whorl  pinnaforme  fragment  SMITH,  preserved  as  an  p. 261, p i . 13;  internal  mould  p i . 14.  in  a  tectonically sheared silty mudstone.  MEASUREMENTS: DESCRIPTION: a  The specimen has been  subquadrate  keel  of  the  N o t available due to poor preservation.  whorl Spatsizi  section.  The venter  specimen  of  L.  tectonically compressed, but appears is convex, pinnaforme  bearing  to have had  a blunt keel, although the  was almost  completely  lost  during  preparation due to the brittle nature of the rock it is preserved i n . Ornament consists of simple, strongly tubercles.  slightly  rursiradiate,  prorsiradiate These  secondary  secondary  feather-like appearance  bituberculate  ribs  ribs  ribs  appear  extend  to  to the ventral surface.  of  moderate  on  the  the  keel  venter,  density  and relief.  beyond  and impart  the a  Dense,  ventro-lateral  herring-bone  or  88  DISCUSSION: of L. the  Although no trace of the inner whorls o f the  pinnaforme was found, the large whorl fragment holotype  (Smith,  1981).  masseanum by virtue of the L.  Pinnaforme.  In  L.  pinnaforme  less compressed  addition,  L.  pinnaforme  can  representative  is identical to the outer whorls of  be  distinguished  whorl section is  single Spatsizi  from  Tropidoceras  and less distinct keel seen i n  bituberculate  whereas  T.  masseanum  is  unituberculate.  OCCURRENCE: pinnaforme  Smith (1981) has  Zone  of  the  western  erected United  L.  States.  Smith for the Pliensbachian, found below the Dubariceras  freboldi.  With  the  exception  pinnaforme  of  This  range an  as  is  the  the  o f the  index  lowest  superjacent  unconfirmed  occurence  fossil for  zone  the  L.  recognized  by  zonal index fossil, of  L.  pinnaforme  from the Queen Charlotte Islands, also reported by Smith (1981), the Spatsizi specimen L.  pinnaforme  is the  first  representative  of this genus  from a  of  known locality in British  Columbia. Localities: AGE;  130.  Early Pliensbachian ( L . pinnaforme  Zone).  Family E O D E R O C E R A T E D A E Genus Metaderoceras  TYPE  SPECTFS:  Ammonites  muticus  SPATH,  SPATH,  D'ORBIGNY,  1929  1925  1844,  p.  274,  pi.  8,  by  original  has been,  and  remains,  designation.  DISCUSSION: somewhat  The taxonomic position of the genus  uncertain. Its  assignment  to the  Metaderoceras  family Eoderoceratidae  relationship of the species attributed to Metaderoceras.  to  other  is unquestioned, but genera  within  the  this family,  89  most notably Crucilobiceras Metaderoceras new al.,  genus  and Eoderoceras,  and designated was subsequently  Ammonites  muticus  synonymized with  D'ORBIGNY  Crucilobiceras  as the type species. i n the Treatise  crucilobatum  BUCKMAN.  narrow whorl  Whereas  muticus,  section. Futhermore, a range  et.  based on  and the type species of Crucilobiceras,  Crucilobiceras  section, Metaderoceras  This  (Arkell  1957). Mouterde (1970), however, moved to retain the genus Metaderoceras  differences between its type, Ammonites  a  is problematic. Spath (1925) created the genus  C.  is characteristically bituberculate and has  is unituberculate and has a generally wider  discrepancy exists  between  the two genera;  whorl  Crucilobiceras  restricted to the Upper Sinemurian Raricostatum  Zone whereas Metaderoceras  in  i n the Ibex Zone. Donovan and Forsey  the Jamesoni  (1973)  Zone  a n d . is most  the  Treatise  followed  Crucilobiceras  and stated  d'Orbigny  probably  is  in  that  an  abundant considering  the  illustration  idealized  Metaderoceras  a  of  Ammonites  the  and unreliable  type,  composite  junior  of  first  is  appears  synonym  of  muticus,  by  about  nine  whorl  fragments. Subsequent Mouterde  (1978),  Metaderoceras, gradation  Da  although  between  Metaderoceras genus,  workers  have  Rocha  adopted  (1977),  Mouterde  the  genera  different  and  (1977)  Geczy  points  Eoderoceras  generic (1976)  out that  and  assignments. have  retained  there  exists  Crucilobiceras  that  and Smith  (1981)  relegated  Metaderoceras  to subgeneric  rank  and  the  genus  a morphological is  beirense. Wiedenmayer (1977, 1980) considered Crucilobiceras  Dubar  bridged  by  to be the valid within  the genus  Crucilobiceras.  The (1981)  who placed  Eoderoceras  AGE  use of the genus  Metaderoceras  on  here  equal  follows the work  generic  ground  with  of Donovan et al. Crucilobiceras  and  .  A N D DISTRIBUTION:  is found  Metaderoceras  Metaderoceras  is characteristically Tethyan i n distribution; it  i n Morocco, the Iberian Penninsula, Hungary,  and western North  America. The  90  genus ranges from the Jamesoni Zone to its acme i n the Ibex Zone.  Metaderoceras  muticum  (D'ORBIGNY,  1844)  Plate 3, fig. 4a, b, 5; plate 4, fig. 1-3.  *1844  Ammonites  muticus D ' O R B I G N Y , p. 274, p i . 80,  1909  Deroceras  non  1958  Crucilobiceras  1965  C. cf. muticum ( D ' O R B . ) - B R E M E R , p. 155.  71970  cf.  Acanthopleuroceras  1- 3.  ( D ' O R B . ) - R o s e n b e r g , p. 265, p i . 13, fig- 7.  non  muticum  fig.  muticum  ( D ' O R B . ) - D O N O V A N , p. 36, pi.  southerlandbrowni  FREBOLD,  p. 440, pi.  3, fig. 2.  1, fig. 1.  1976  M.  1981  C . cf. M. muticum ( D ' O R B . ) - I M L A Y , p. 35, p i . 7, fig. 6-10,  1981  C. cf. M. muticum ( D ' O R B . ) - S M I T H , p. 236, fig. 1-2; pi. 9, fig. 1.  71981 MATERIAL:  muticum ( D ' O R B . ) - G E C Z Y , p. 56, p i . 11, fig. 3,4.  Uptonia  Forty  cf. ignota ( S I M P S O N ) - H I L L E B R A N D T , p.  three  specimens,  preserved  mainly  as  510, pi.  external  12- 15.  5, fig- 4.  moulds  with  some  internal moulds, i n siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-90823  39  19  49  11  9.5  16  C-103305(A)  60  31  52  -  -  18  C-103305(B)  c80  c43  51  -  -  cl8  - --  c43  c22  51  -  -  14  C-90527  60  31  52  -  - --  31  15  48  8.5  C-90839  cl84  107  58  -  _  cl07  63  59  _  —  .  c43 c26  16 16 31 21  91  c63  30  48  14  cl7  C-90924  46  C-103104  DESCRIPTION: and  quite  convex;  Shell  shallow;  28  cl07  60  56  c24  21  c60  30  50  cl6.5  17  evolute;  umbilical  whorl wall  section  rectangular  low, convex;  to subquadrate.  umbilical  edge  Umbilicus  wide  rounded. The flanks are  ventral shoulder is sharply rounded. Venter is broad, convex, and smooth  except  for faint swellings that arch adorally from the tubercles on the ventral shoulder i n some specimens. Ornament collection.  appears  A t diameters  on  the  innermost  less than about  whorls  observed  20 m m , ribbing consists  in  specimens  of fairly  straight, rectiradiate  to slightly prorsiradiate ribs that arise at or just above  edge  at the ventral shoulder i n small tubercles.  20  and terminate m m , the  ribs  arise  faintly  rursiradiate. They gradually increase  on  the  umbilical  wall  i n strength and become  they  this  dense, simple, the umbilical  A t diameters  where  of  may  greater be  than  slightly  rectiradiate to prorsiradiate at  about 1/4 of the whorl height They then continue straight to the ventral shoulder where they  terminate  in large  tubercles  density is fairly low (between increases  The increase  the  bases  of  Mediterranean region. Dubar and Mouterde (1978) state that  any specimens  observed  to 27 P R H W  by Dubar and Mouterde (1978) in specimens  from 18 P R H W  from  rib density on the last  on the penultimate whorl. Unfortunately,  are given to indicate the diameter at which  figured.  spines. R i b  i n rib density at large diameters i n the Spatsizi specimens of  the  no measurements  sharp  mm) diameters.  muticum  increases  long,  up to diameters of about 100 mm) but  M.  whorl  has also been  represent  13 and 18 P R H W  gradually at large (>100  DISCUSSION:  that  this change occurs, nor are  92  Based  on observations  (1981) reports a change 100  of specimens  m m the whorl  change  i n shape  material whorl  section  is  comment  change  and Nevada, Smith than about  section is subquadrate- higher than wide whereas at slightly  on the whorl  reported  Oregon  at diameters greater  depressed.  Smith  may be indicative of maturity. The poor  precludes  section  from  i n whorl section of M. muticum  m m . A t D < 1 0 0 m m , the whorl  D>100  collected  by Smith  section,  (op.  cit.)  preservation  states  this  of the Spatsizi  however, the coincidence  (op. cit.) and the rib density  that  between the  increase  i n the  Spatsizi material at diameters greater than 100 m m should be noted.  OCCURRENCE: region  M.  muticum  is a  Carixian  form  (Morocco, Hungary) and in the western  that  United  is found  i n the Mediterranean  States, Southern  Alaska,  Queen Charlotte Islands. In Spatsizi it occurs within the range of Dubariceras Tropidoceras  and the  freboldi and  .  Localities: 1, 3, 4, 8, 9, 10, 13, 63, 64, 79, 95, 99-101, 112, 139, 141. AGE:  Early Pliensbachian (D. freboldi Zone).  Metaderoceras  aff. M.  muticum  Plate 5, fig. 1-3.  71981  Crucilobiceras  cf.  C.  densinodulum  B U C K M A N - I M L A Y , p.  34,  p i . 7,  fig.  4,5. MATERIAL:  Six specimens,  poorly to moderately  well preserved as external  and internal  moulds i n siltstone and fine sandstone.  MEASUREMENTS; SPECIMEN  D  LTD  U  WH  WW  PRHW  C-103156  c90  c55  61  c21  -  cl3  93  DESCRIPTION: low, steep;  Shell  evolute,  umbilical edge  whorl  section  rectangular  rounded. Flanks are  convex;  to  sub-quadrate.  Umbilical  wall  ventral shoulder abruptly rounded;  venter is broad and low. Ribbing on the  the  on  the  inner whorls consists  umbilical wall  ventro-lateral  become  where  shoulder  they by  of  fairly dense  prorsiradiate  trend slightly rursiradiately. Each  a  long,  sharp  tubercle.  On  the  rib  ribs  that  is terminated  outer  whorls  the  The inner whorls ( D  muticum  i n rib  muticum  becomes  density and  coarser  assigned to Crucilobiceras  cf. C.  specimens  of Af. aff.  densinodulum  mm) of Af. aff. Af. muticum are similar to  than  at in  larger Af.  diameters  muticum.  densinodulum  A  the  ribbing of  single  specimen  Spatsizi  muticum  (or  C.  exception  to this  in the sequence,  Alaska,  by Imlay (1981), is similar to the  Spatsizi  ornament on the inner whorls of C . cf. C.  and  Alaska,  C.  Af.  muticum  densinodulum)  exists  share  in Spatsizi where  (or  C.  the  same  one  apparently below the other occurrences  is similar  cit.).  cf.  specimen  densinodulum  C.  muticum)  stratigraphic (pi. 5,  fig.  and  Af. aff.  position. A 2)  was collected low  of Af. muticum.  The similarity i n  Spatsizi and Alaskan collections suggest  a close affinity between  C . cf.  dimorphs?) of the and the  apparently  densinodlum  C.  densinodulum).  same species.  A  Indeed,  occurs  in  whorl the  section lower  may  direct comparison between  illustrations of C . densidodulum wider  they  and  part  of  the  Af. muticum well  be  A f . aff.  age  Upper  of  the  Sinemurian  the  and Af. aff.  variants  (or  even  Af. muticum  from  from Europe is not made  younger  Af.  possible  with the coincident stratigraphic ranges of both  (or  C.  appears  ornament on the inner whorls together  muticum  Af.  from  muticum also Figured by Imlay (op.  cf.  M.  Af. aff.  tend to weaken near the middle of the flanks and its whorl section  to that of C . cf. C.  the  ribs  Af. muticum except that the ribs on the outer whorls of C . cf.  more compresed. The  In  <50  form, but  much  Spatsizi  at  distant, fairly broad, and faint on the lower flank.  DISCUSSION:  Af.  arise  Spatsizi  here  due  specimens  Raricostatum  Zone  to (C. in  94  Europe). It is interesting to note, however, that Bremer (1965) considered C. densinodlum to be a subspecies of M. muticum.  OCCURRENCE: M.  muticum  occurs with and possibly below  in Spatsizi. In its lowest position, M. aff. M. muticum  Acanthopleuroceras Pinnaforme  As noted above, M. aff. M. muticum  cf. A. stahli and M. evolutum.  and lower Dayiceroides  is associated with  This range roughly corresponds to the  (Freboldi) Zones of Smith (1981), or to the Jamesoni  and Ibex Zones of northwest Europe. Localities: 5, 15, 73, 104, 142. AGE: Early Pliensbachian (L. pinnaforme to Lower D. freboldi Zone).  Metaderoceras  evolutum (FUCINI,  1921)  Plate 6, fig. 3.  1899  Deroceras  gemmellaroi  1909  Deroceras  muticum D'ORBIGNY-ROSENBERG, p. 265, pi. 13, fig. 7.  •1921  Deroceras  evolutum FUCINI, p. 50, pi. 1, fig. 14a, b.  1963  Crucilobiceras  LEVI-FUCINI, p. 16, pi. 20, fig. 1, 2.  aff.. evolutum (FUCINI)-DU DRESNAY, p. 147, pi. 2, fig. 2,  3. 1970  71976  Crucilobiceras  Metaderoceras  paciftcum  FREBOLD, p. 435, pi. 1, fig. 4-8.  sp. aff.. M. evolutum  (FUCINI)-GECZY, p. 61, pi. 12, fig.  5. 1977  Crucilobiceras  evolutum  (FUCINI) bruntum WIEDENMAYER, p. 59, pi. 13,  evolutum  evolutum  fig. 1. 2. 1977  Crucilobiceras  fig. 3.  (FUCINI)-WIEDENMAYER,  p. 59, pi. 13,  95  1978  Metaderoceras  evolutum D U B A R  1978  Metaderoceras  evolutum  and M O U T E R D E , p. 44, p i . 2, fig. 1.  (FUCINI)  bruntum  (WIEDENMAYER)-COLERA  et  al., p. 311, p i . 1, fig. 3a, b, c, 4. non  1978  Metaderoceras  sp. 3 (gr. M.  evolutum F U C I N I ) - C O L E R A  et al., p. 314, p i .  1, fig. 2; p i . 2, fig. 2. 1980  Crucilobiceras  evolutum  evolutum  (FUCINI)-WIEDENMAYER,  p.  48,  p i . 1,  fig. 3, 4. 1981  Crucilobiceras  (Metaderoceras)  evolutum ( F U C I N I ) - S M I T H ,  p. 231, p i . 8,  fig.  2, 3, 5; Text-fig. 6-10. cf.  1981  Crucilobiceras  cf. C. pacificum  FREBOLD-IMLAY,  p. 35, p i . 8, fig. 10-12,  15-17. cf.  1983  Metaderoceras  MATERIAL:  T w o specimens  evolutum ( F U C I N I ) - R I V A S ,  p. 395, p i . 1,  fig.  1-8.  preserved as internal moulds i n limestone.  MEASUREMENTS SPECIMEN  D  UD  U  WH  WW  PRHW  C-81970(A)  31  16  52  c9  c6  cl3  C-81970(B)  c40  c21  52  -  -  -  DESCRIPTION:  Shell  evolute;  whorl  section  rectangular to  sub-quadrate.  low, shallow; umbilical edge rounded. Flanks are slightly convex; rounded. The venter Ornament ribs Faint  arise  above  secondary  ventral shoulder abruptly  is fairly broad, convex.  consists  of distant,  straight,  the umbilical edge ribs  Umbilical  or inter-rib  slightly prorsiradiate  and terminate  lirae  are visible  in prominant on these  ribs of low relief. The ventro-lateral  specimens.  tubercles.  The venter  is  featureless.  DISCUSSION:  Metaderoceras  evolutum has been  the subject of much  study and revision  96  over the last half century. A recent study by Rivas (1983) has shown A f . evolutum a variable species subspecies.  that  Although  mouterdi is retained  includes many  specimens  previously assigned  to other  to be  species and  Rivas (1983) includes Af. mouterdi ( F R E B O L D ) i n A f . evolutum, Af. i n this thesis  based  on differences  observed  i n the outer  whorls of  specimens of Af cf. Af. mouterdi from Spatsizi (see the following discussion of Af. cf. Af. mouterdi). The possibility remains, however, that  the two forms are variants of the same  species.  OCCURRENCE:  A f . evolutum  is common  i n Pliensbachian  (Jamesoni- Margaritatus  sequences i n the Mediterranean region. The Spatsizi specimens of A f . evolutum low i n the sequence, with  below the range  Acanthopleuroceras  of Dubariceras  cf. A. stahli. This occurrence  freboldi.  They  occur  Zones)  were found  i n association  corresponds to the Pinnaforme  Zone  of Smith (1981) and is roughly equivalent to the Jamesoni Zone o f northwest Europe. In the  Queen  Charlotte  Islands  (Frebold,  found slightly higher in the section;  1970) and Alaska  it occurs  with  (Imlay,  Dubariceras  1981) Af. evolutum  freboldi  and  Tropidoceras  sp.. Localities: 138. AGE:  Early Pliensbachian (L. pinnaforme to ?Lower D. freboldi Zone).  Metaderoceras  cf. A f . mouterdi ( F R E B O L D ,  1970)  Plate 5, fig. 4, 5; plate 6, fig. 1.  cf.  *1970  MATERIAL:  Crucilobiceras  mouterdi F R E B O L D , p. 437, p i . 1, fig. 2a, b.  Seven specimens, preserved i n siltstone as external and internal moulds.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  is  PRHW  97  C-90843(A)  78  43  55  20  - --  -  c43  25  58  cll.5  10  - - -  c25  12  48  -  11  C-103309  44  21  48  12  11  - - -  c22  10  45  7  14  C-103307  cllO  c51  46  28  - - -  c49  c24  50  -  13  - - -  c24  clO  42  -  16  DESCRIPTION: convex;  Shell  evolute;  umbilical slope  dimension angular.  at  The  the  is  wide  Whorl  section  gentle.  ventral  venter  umbilicus  shoulder.  broad,  lowly  that arch adorally from tubercles Ornament and  consists,  umbilical  varies  on  edge,  the  with  greater than about  to  PRHW.  10-11  This  by Frebold (1970, see different  from the  whorls,  of  a  rather  mm. reach  a  smooth  Umbilical w  sub-quadrate  with  and  the  ventral  except  for  very  widest  shoulder  faint  is  swellings  at a diameter  straight,  terminate  slender  in  distinct  rib  ribs  of less than 5 m m that  tubercles.  arise At  on  umbilical  a decrease from 13-14  density is most apparent  in the  the  PRHW  holotype figured  the following discussion). The ribs of this reduced-density stage are ribs  i n that they are  indistinct on the  and quite broad towards the  two largest specimens  dramatic increase  At UD=45  dense,  and  the ventral shoulder i n large tubercles The  and  be  convex  10 mm, rib density undergoes  decrease in  earlier  then become stronger  are  to  deep.  23  on the ventral shoulder.  rectiradially,  diameters  appears  flanks  convex  moderately  growth. Ribbing appears  inner  trend  The  and  17  ventral shoulder. The  that represent  of M.  lower 1/3 ribs  maximum density of  specimens  cf. M . mouterdi in the  about  24  have  exceeded  PRHW.  The  flanks  terminate  at  the bases of spines. Spatsizi collections  i n rib density beginning at an umbilical diameter  m m , both  of the  a ribs  rib  density  of  20  show  of about PRHW,  of this high density stage  different from those of the preceeding stage; they arise on the umbilical wall where  25 and are they  98  trend  rursiradiately,  where they are tubercles.  The  compressed  about  high  The  1970)  section  of  this  and  trend  densely  Spatsizi specimens  in  mm,  their  although  magnitude  in  of  19  PRHW  material  is  from  specimens  forward  slightly  ribbed  prorsiradiarely  on  the  flank  at the ventral shoulder by sharp  stage  appears  to  be  relatively  more  than earlier whorls.  27  greater  curve  very gently sinuous. They are terminated whorl  DISCUSSION: (Frebold,  then  volution and  form  the  in  the to  14  of Af. cf.  decrease  holotype.  to  10  of  rib  12  are probably conspecific  rib  PRHW,  PRHW.  In  ribbing at  density,  Whereas  a low of  Af. mouterdi are similar to the  spite  to Frebold's  beginning  density  the  umbilical diameters  in  the  corresponding  of  this  at  UD=10  holotype  holotype less  mm,  drops  decrease in the  numeric  difference,  (1970) Af. mouterdi, based  than is  of  from  a  Spatsizi  the  Spatsizi  on the  similar  rib form and the fact that all the secimens exhibit a marked rib density decrease. The high rib density stage observed on the outer whorls of the (a  stage that possibly  mouterdi. This  high  the  represents the density  diameter  of  holotype,  (UD=26  mm). In other  to the onset of the on  the  internal  interpretation  as the  first  which,  ribbed  of  develops  these  body chamber,  having a more a  density  densely  more  the  Frebold  suture  numerous  of the  is  the  septate  holotype  roughly  of Af.  maximum  to  the  end  corresponds  The  absence of  lends  support  to  their  it is difficult to determine  whether  the  lack  outer  whorls  sutures  preservation.  inner  line. It ribs.  (1970),  specimens  holotype  exceeding  Spatsizi specimens.  ribbed  although  seen i n the  diameter  to  species of Metaderoceras middle whorls. It  variable rib density with growth (fig 6.1),  less complicated  having  from  a  greatest diameter  Af. mouterdi is unique among the rib  at  to  stage of the  of sutures is due simply to poor  decreasing  chamber) is not  according  words, the  dense  moulds  stage  body  Spatsizi  Af.  differs  from  mouterdi  is  both  Af.  differs  i n its tendency from  toward  Af. muticm  in  and according to Frebold (1970) beirense  distinguished  from  and  Af.  venarense in  Af.  evolutum  by  the  40  Dubariceras freboldi (this study) Dubariceras freboldi ( S m i t h . 1 9 8 1 ) Dubariceras freboldi (Frebold,1970) Metaderoceras silviesi (Smith,(1981) Metaderoceras silviesi (this study) Metaderoceras mouterdi (Frebold, 1970) M e t a d e r o c e r a s c f . M. m o u t e r d i ( t h i s s t u d y ) M e t a d e r o c e r a s muticum ( d . O r b i g n y M e t a d e r o c e r a s muticum ( t h i s s t u d y )  1  —i—  20  10  30  40 UMBILICAL  FIGURE  6.1  50  60  DIAMETER  70  of  Dubariceras  freboldi  and  100  (mm)  Graph comparing rib density between members of the fields  90  80  Metaderoceras  family  silviesi  are  Eoderoceratidae. distinct  Points  The for  Metaderoceras muticum and M. mouterdi are somewhat clustered. However, rib density of M. mouterdi is more variable than that of M. muticum, and shows a distinct decrease (at 1 0 m m < U D < 3 0 m m ) followed by a marked increase (at UD>30mrn).  100  absense  of  synonymized  ribs  joining  at  Af. mouterdi  mouterdi have been  the  with  ventro-lateral  Af. evolutum.  collected that  tubercles,  although  Unfortunately, so  Rivas  (1983)  few specimens  a more precise comparison between  has  of A f .  the two genera is  difficult  OCCURRENCE:  Only  two specimens  of Af. mouterdi have been  locality on the Queen Charlotte Islands. These Dubariceras  with  freboldi,  Tropidoceras  and Af. evolutum.  and Dubariceras  are found i n association with  Similarly,  freboldi,  reported from the type  i n Spatsizi,  Af. cf.  although A f . evolutum  Tropidoceras,  A f . mouterdi  is  found  appears to occur below  Af. cf. M . mouterdi here. Localities: 5, 7, 64. AGE:  Early Pliensbachian (D. freboldi Zone).  Metaderoceras  silviesi ( H E R T L E I N ,  1925)  Plate 4, fig. 4, 5; plate 7, fig. 1.  •1925 1981  Uptonia silviesi H E R T L E I N , p. 39, p i . 3, fig. 1, 2, 5. Crucilobiceras  (Metaderoceras)  silviesi  (HERTLEIN)-SMITH,  p.  239,  pi.  11,  fig. 1. 1981  71981  Crucilobiceras  Uptonia  cf.  cf. U.  C . submuticum  (OPPEL)-IMLAY,  obsolete ( S I M P S O N ) - V O N  p. 33, p i . 5,  HILLEBRANDT,  fig.  1-3.  p. 509, p i . 5,  fig. 1, 2, 5. MATERIAL:  Twenty one specimens preserved as external moulds with rare internal moulds  i n siltstone.  MEASUREMENTS; SPECIMEN  D  UD  U  WH  WW  PRHW  101  C-88231  cl50  c75  50  c43  -  - - -  cl06  c53  50  c22  21  C-103324{M1)  37  18  49  clO  cl4  DESCRIPTION:  Shell  evolute;  directly observed in the wall is low, steep;  whorl  section  appears  to  be  rectangular  but  cannot  Spatsizi collections due to incomplete preservation. The  umbilical  edge rounded. Flanks are slightly convex;  be  umbilical  ventral shoulder is  abruptly rounded. The venter is low, slightly convex, and fairly broad. Ornament consists of dense, simple, straight to slightly sinuous ribs. The ribs arise on  the umbilical wall  become ventral  prorsiradiate and continue shoulder each  continue  where they appear to trend slightly rursiradiately, then  onto  the  rib bears  venter  more  or  less  straight to the  a prominent tubercle. The  from the  tubercles  but  decrease  subsequently  ventral shoulder. A t the  ribs then project in strength.  forward and  O n larger whorls  the ribs form ventral chevrons, although the apices of the chevrons tend to be faint.  DISCUSSION: the  genera  dense, more  Metaderoceras  Metaderoceras  relatively coarsely  tend  and  finely ribbed  appears  Dubariceras inner  to  whorls are  of Metaderoceras  become  slightly  beyond  the  the  ventral  region  ventro-lateral  communication,  1985),  of  tubercles  but  ventral chevrons  of  communication, dubariceras,  ribs of the  between  1985).  whereas  middle and  coarseness,  low  ventral  Italy.  A s pointed out  in the  outer  density,  an  specimens  of  M.  silviesi,  chevrons? According adult characteristic  to of  the  ribs  M. and  preceeding  description of  project  Mouterde (written Metaderoceras,  they also occur faintly on the outermost whorls of some specimens of Dubariceras from  the  The ribs on the outer whorls of their  Its  of D. freboldi.  form are  written  dense  again,  larger  and  morphologically intermediate  reminiscent  (fig. 6.1).  ribbing  the  be  and less  sinuous,  tuberculation set them apart from the On  to  (Mouterde,  ribbed, distinctly tuberculate  whorls are characteristic silviesi  silviesi  Dubariceras  freboldi,  but dubari weak  chevrons are also found on the outer whorls of some of the Canadian specimens  102  (Frebold, 1970; this study). If Dubariceras  evolved from Metaderoceras  as Dommergues et.  al. (1984) conclude, then it follows that the ventral chevrons observed i n Dubariceras an ancestral  feature  derived from Metaderoceras.  to illustrate the close general, and between  OCCURRENCE: region  The presence  phylogenetic relationship between  Smith  Metaderoceras  serves  and Dubariceras  in  M. silviesi and D. freboldi i n particular.  Metaderoceras  silviesi  appears  to  be  (see synonomy). In Spatsizi, it is found within  although  of ventral chevrons  are  (1981)  found  association with Luningiceras  it  to occur  restricted the range  i n the zone  below  to  the  eastern  Pacific  of Dubariceras Dubariceras  freboldi,  freboldi,  in  pinnaforme.  Localities: 4, 5, 8-11, 19, 64, 93, 98, 100, 104, 141. AGE:  Early Pliensbahian D. freboldi Zone.  Metaderoceras  sp.  Plate 6, fig. 2.  MATERIAL: volcaniclastic  A  single  specimen  preserved  as  an  external  mould  in  fine  grained  sandstone.  MEASUREMENTS;  SPECIMEN  D  UD  U  WH  WW  PRHW  C-103303  53  28  53  14  -  20  c28  17  61  c8.5  -  20  DESCRIPTION: wall  Shell is evolute; whorl section  low, shallow to moderately  ventral  shoulder  appears  to be  steep; abruptly  is unknown due to preservation.  umbilical edge rounded;  rounded;  the venter  flanks  Umbilical  are convex. The  is not observed  i n this  103  specimen. Ornament  consists  of  straight,  moderately  prorsiradiate  particularly on the inner whorls, "and remains fairly constant specimen. 1/3  The  the  ribs  flank  arise  height  on  The  the ribs  lower flank are  fairly  and  broad  attain and  ribs.  Rib  density  is  throught the ontogeny their  high,  of this  maximum relief at  continue  to  the  ventral  about  shoulder  where they bear a ventro- lateral spine. The ornament of the ventral region is unknown.  DISCUSSION: density,  but  is  Metaderoceras sinuous  This  than  specimen  similar sp.  is  those  marked contrast  to  to  M.  less than of the  M.  differs  from  Metaderoceras  muticum  in  most  that  M.  silviesi,  silviesi.  of The  highly variable  constant rib  other  density  respects.  and  rib  muticum  the  density  seen  The  ribs of  in the  by  its  higher  expansion  are  rate  broader  and  Metaderoceras ontogeny  of  rib  sp. M.  of less  is in cf. M .  mouterdi.  OCCURRENCE: low  in  the  Tropidoceras  Pliensbachian  section  is  possibly  situ, it apparently came from very  from  the  same  stratigraphic  level  as  1),  by  low  to  1.  Early Pliensbachian (?Lower D. freboldi Zone).  Genus Dubariceras  TYPE  and  was found ex  sp.  Localities: AGE:  Although the specimen  SPECIES:  subsequent  dubari  M O U T E R D E and R I V A S ,  DOMMERGUES  et.  al.  (1984,  p.  1984  382,  pi.  designation.  REMARKS: moderate,  Dubariceras  DOMMERGUES,  Shells  evolute;  platyconic,  whorl  section  rectangular.  Umbilical  wall  convex, steep; umbilical edge rounded. Flanks are flat to slightly convex. Ventral  104  shoulder abruptly rounded; venter is low, slightly convex. Ornament consists of dense ribs that arise on the umbilical wall where they trend rursiradiately,  then  subsequently  describe  a  sinuous  pattern  up  ventro-lateral tubercles beyond which they fade rapidly on the The accomodate erroneously  genus  Dubariceras  certain  was created  Carixian ammonites  assigned  to  the  genera  by  of  Dommergues  Tethyan  Uptonia,  According  to  Dommergues  surrounding  assignment  of  the  that,  the  generic  although  they  are  EODEROCERATIDAE),  show  a  AGE  Carixian  Penninsula). In  al.  cit.)  until and  (op.  Dubariceras  related  to  remarkable  to  elongate  i n order  now,  have  Dayiceras  cit.),  the  stems  from  been  (family confusion  Metaderoceras  morphologic  to  convergence  the  fact  (family to  the  Spatsizi collections, the creation of  the  seems justified.  A N D DISTRTBIJTION:  Upper  which,  of  Polymorphitids. Based on evidence provided by the genus Dubariceras  et.  members  phylogenetically  they  al. (op.  Platypleuroceras,  POLYMORPHITIDAE).  flanks  venter.  et.  aspect  the  of  the  the  Dubariceras  Tethyan  New World,  is  region  a  Tethyan  (Hungary,  Dubariceras  occurs  form Italy,  found i n the Morocco,  in the  and  Middle the  and  Iberian  Andes mountains and i n  the  western United States, British Columbia, and southern Alaska. It is significant that the two known areas. to  the  species D.  of  Dubariceras;  dubari is restricted western  Americas.  D. to the  The  freboldi  and  D.  occupy  disjoint  geographical  Mediterranean region, while D.  freboldi  is  paleobiogeographic  dubari,  implications  of  this  restricted  distribution  discussed in the chapter on paleobiogeography.  Dubariceras  freboldi  DOMMERGUES,  Plate 7, fig 1-4;  •1970  Uptonia  M O U T E R D E , and R I V A S ,  1985  plate 8, fig. 3, 4.  dayiceroides M O U T E R D E - F R E B O L D ,  p. 438,  p i . 1, fig. 9a, b, c  are  105  1981  Uptonia  8, 1981  cf.  U.  dayiceroides  (MOUTERDE)-IMLAY,  p.  36,  p i . 9,  fig.  1-4,  12-16.  Dayiceras  dayiceroides  (MOUTERDE)-SMITH,  p.  265,  pi.  12,  fig.  4-8,  text-fig. 6-14. 1981  Uptonia  cf. U.  angusta ( O P P E L ) - v o n H I L L E B R A N D T ,  p. 509, p i . 5, fig.  3a, b. 1983  Dayiceras  dayiceroides  (MOUTERDE)-SMITH,  p.  86,  fig.  2a,  b,  c  (1981  material partly refigured). 1984  MATERIAL:  Dubariceras  freboldi  Approxomatelv  one  DOMMERGUES  hundred  eighty  et.  al. fig. 3 - A 3 .  specimens  preserved  as  external  internal moulds in siltstone and minor limestone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-90832(D1)  74  30  43  26  9  34  C-90836  16  6  37  c6  29  C-90830  63  25  40  20  34  C-90843(D1)  -  -  -  c43  cl6  C-103324(A)  cl05  47  45  31  12  47  22  47  16  c44  c22  50  cl3  30  14  47  cl3  -  C-103318  -  -  -  15  11  C-103105  cl25  53  42  c43  29  C-103306  61  25  41  -  29  C-103314  DESCRIPTION: growth.  Shell  evolute:  whorl  Umbilical wall is low, steep;  section  rectangular,  27  becoming more  compressed  umbilical edj>e is abruptly rounded. The flanks  106  slightly convex  on the  smaller whorls but tend  to  become  flatter  on larger  whorls.  The  ventral shoulder is abruptly rounded; the venter is low, flat to slightly convex. Ornament consists of simple, dense, sinuous ribs that appear at diameters 2-3  of  about  m m (only a single exception to this was found in a small specimen of about  25mm  diameter  which  shows sporadic fasiculation or bundling of ribs into pairs just above  umbilical  edge).  The ribs arise on the umbilical wall where they trend rursiradiately. Just  above 1/3  the of  slightly  umbilical edge the  the  flank  height  prorsiradiately  become  increasingly  elongate  tubercle  projecting  the ribs project  The  up  the  ribs  then  flanks.  As  prorsiradiate.  beyond  extensions  ribs curve gently  which  of the  At the  ribs,  forward to  curve the  the  gently  ribs  ventral  ribs  fade  approach shoulder  rapidly.  dayiceroides),  Frebold  from  the  and  (1970)  drew  Queen  those  however,  (taxonomic) the  consequence.  Portuguese  the  rectiradiately  ventral  each  rib  for  shoulder  bears  these  O n some  of the  ".  the  which  described that  freboldi (then  as  the  he  to they  a  radially  faint  adorally  larger whorls,  Uptonia?  . . The  Charlotte  and  to  Uptonia  between  Uptonia  dayiceroides  only difference  material may be restricted  Queen  assigned to  similarity  assigned  by  seems  cf.  U.  Mouterde to  be  the  Frebold concluded  that  material  was  of  little  of a size comparable  in the Queen Charlotte collections to corroborate  conclusion. Where visible, the venters of small specimens  the  to the inner whorls and  Portuguese  Unfortunately, there were no specimens  material present  show any sign of a keel.  striking  faint keel i n Mouterde's species".  the crenulated keel of the Portuguese between  to  Islands,  Portugal,  presence of a weakly crenulated  difference  attention  Charlotte  from  (1951). Frebold pointed o u t  this  trend  i n the Queen Charlotte material.  In the original description of Dubariceras  that  to  Except  the venter is featureless.  DISCUSSION:  dayiceroides,  again  about  forward onto the venter and form indistinct chevrons. Frebold (1970) also  noted this feature  specimens  trend prorsiradiately to  the  in the Spatsizi collections  to  Frebold's do not  107  Smith from  (1983)  Oregon,  also  Nevada,  considered and  Alaska,  dayiceroides.  Smith  concluded,  Uptonia,  to  genus  but  the  the  Queen  to  however,  be  Charlotte  conspecific  that  the  material, with  species  as  the  well  as  Portuguese  dayiceroides  material Uptonia?  belonged  not  to  Dayiceras.  Recently, Dommergues et al. (1984) included all the western N o r t h American forms attributed  to  consider  that  American  Uptonia-  sufficient  material  dayiceroides. Dayiceras  or  Dayiceras  morphological differences  to  retain  According to  dayiceroides  1) There  is  crenulated,  as  et.  into  Dubariceras  exist  between  (1951) al.  Uptonia  (1984),  freboldi.  the  However,  Portuguese  dayiceroides  Dubariceras  and  in  freboldi  they  North  Dayiceras  differs  from  follows:  a  trace,  more  or  less  from  Mouterde's  Dommergues  never  dayiceroides  dayiceroides  Portugal  in  Dubariceras  distinct (phrase  keel" in  freboldi, observed  quotes  of in  the  the  translated  "occasionally  specimens  from  of  slightly Dayiceras  Dommergues  et.  al.,  1984). .  2) The venter of Dubariceras the  whorl  as  in  It appears that  are  section  Dayiceras  may  also  remains  is flatter than that of Dayiceras  rectangular  with  found i n  be  significant  the  that  overlying beds  been  i n the  freboldi  OCCURRENCE:  Dubariceras  Pliensbachian  i n Spatsizi (see  freboldi sections  abscent in time equivalent sections  Portuguese other,  (Mouterde,  observed, although a  with Dubariceras  in  growth (i.e.,  it does  dayiceroides, not  become  and ogival  dayiceroides).  to pass (morphologically) upward into  such transition has  common  freboldi  Dayiceras  less ambiguous  1951).  In  few specimens  western of  the  on the  to the  western North  East  Cordillera  North  dayiceroides of  Dayiceras  America, no sp. are  found  Dayiceras).  Pacific of  species  Dayiceras  the following discussion of  is restricted of  sections  faunal realm. It  North  is  America but  is  American craton. In South America,  D.  freboldi is found i n Lower Pliensbachian rocks in Chile (von Hillebrandt, 1981a). Although  108  D.  freboldi  is  unknown  in  the  represents the genus around the In  Mediterranean  region,  the  related  species  D.  dubari  rocks that are  roughly  Mediterranean.  Spatsizi, D. freboldi is abundant  in Lower Pliensbachian  equivalent to the Ibex and Davoei Zones of northwest Europe. In its lowest position, it is associated  with  Tropidoceras  Uptonia  sp.,  Dayiceras  sp.. Higher i n the  Reynesocoeloceras  cf.  R.  sp.,  Metaderoceras  sequence it occurs  western  Islands North  illustrates  America. The  Early Pliensbachian  use  (D.  REMARKS: genus the  The  various workers  systematic Fischer  sp. A and B,  and  D.  freboldi  as  a  (1981) erected  as a zonal index  i n Spatsizi and the  zonal  Queen  Lower Pliensbachian  index  fossil  in  Spatsizi  of is  101,  102.  Zone).  COELOCERATJDAE H A U G , Reynesocoeloceras G E C Z Y ,  crassum  99,  YOUNG  and  BIRD  1910 1976  var.  indunensis  MENEGHINI,  by original designation.  taxonomic  Aveyroniceras,  of  freboldi  Coeloceras  (p. 72, p i . 16)  and usefulness  13, 15, 16, 19, 21, 22, 64, 72-75, 79, 96,  Genus  1891  and  4.4.  Family  SPECIES:  silviesi,  dayiceroides)  its potential as an index fossil for the  Localities: 4, 5, 7-11,  TYPE  to Dayiceras  North America. Its abundance  discussed in Chapter 4, section  AGE:  Aveyroniceras  M.  in sections in Oregon and Nevada, Smith  D. freboldi (which at that time was assigned  Charlotte  and  incertum.  Because of its abundance  fossil for western  with  muticum,  position  is problematic who have  treatments, the  reader  (1971), Schmidt-Effing  of  the  genus  Reynesocoeloceras  and there does not appear  published on these is referred  forms.  For  and  the  to be a consensus a review of  the  associated amongst different  to Geczy (1976), Pinna and Levi-Setti (1971),  (1972), Wiedenmayer  (1977, 1980), von Hillebrandt (1981b),  109  and Donovan et al. (1981). The compromise relatively  based  on  the  streamlined  taxonomic  system  adopted in this study is essentially  previously published work;  framework  within  which  the  it  is  Spatsizi  designed  as  material  a  may  practical  be  a  and  comfortably  placed. Reynesocoeloceras,  although  originally  defined  Geczy (1976), is given full generic status here, 1980), Donovan et morphologic  al. (1981), and  similarities  between  to  Coeloceras  Reynesocoeloceras Their  ranges  first  do  is  not  in  overlap,  the  follows  the  (1981b).  of  the  of  Geczy  work  Although  Dactylioceratidae,  Donovan  they  do  to  suggesting  genus  and  the  that  and  the  (1976),  Wiedenmayer  et  (1981)  state  that  by  as  evidence  the  of  a  (Donovan  continues  two  genera  et  into  the  are  distinct,  al., 1981),  Davoei  Zone.  and  that  Coeloceras.  Reynesocoeloceras  al.  Coeloceras  (1976) considered  Coeloceras  Jamesoni Zone  R>ex Zone  Reynesocoeloceras is likely a derivative of Assignment  of  the two forms, but stratigraphic evidence is contrary  restricted  appears  subgenus  following the work of Wiedenmayer (1977,  Reynesocoeloceras  relationship between  Whereas  a  von Hillebrandt (1981b). Geczy  generic- subgeneric this.  as  to  the  (1977,  place  family  Coeloceratidae  1980),  and  Reynesocoeloceras  Reynesocoeloceras  was  derived  von  Hillebrandt  into  from  here  the  family  Coeloceratidae.  This illustrates what is probably a close phylogenetic relationship between  the two families  (Dactylioceratidae  in  (Arkell  by  Coeloceratidae),  a  possibility  et. al., 1957,  p. L252) and by Fischer (1971).  A  view for the  contrasting  Dommergues  Reynesocoeloceras the  and  genus  Coeloceras,  and  Mouterde  , which they  Metaderoceras. but  that  origin of  the  They  (1982).  have  named  conclude  similarity between  already  Reynesocoeloceras They  state  ancestry.  has  that  Reynesocoeloceras that the  recently the  inner  whorls  of  did  the  Treatise  been  proposed  earliest  praeincertum,  Reynesocoeloceras  those of Coeloceras is a result of morphological convergence indicates a distant common  considered  not  form  of  evolved  from  evolve  from  Reynesocoeloceras  and  between the two genera,  and  110  The names  name,  Reynesoceras  morphology  from  polyfurcating  its  to  growth.  whorls  Reynesoceras-like  outer  sporadic  Aveyroniceras,  Reynesocoeloceras  the  i n that  the  combination  is characterized  (cadiconic, whorls  of  Prodactylioceras  tubercles  Tethyan  tuberculate  i t . undergoes  a  in  bi-  or  with  simple,  Reynesocoeloceras  differs from Reynesocoeloceras by  of  change  generic  change  with  (serpenticonic  on the outer  equivalent  the  by a  i n morphology that distinguishes  and Reynesoceras.  ribbing,  from  inner  ribs). It is this change  denser  derived  Reynesocoeloceras  Coeloceras-like  both Coeloceras  finer,  is  and Coeloceras.  ribs)  non-tuberculate from  Reynesocoeloceras,  whorls, and its more  Prodactylioceras,  i n ornamentation  is  regular  similar  with  growth  to from  tuberculate, bifurcating ribs on the innermost whorls to non-tuberculate, simple ribs on the outer  whorls.  However,  Reynesocoeloceras Aveyroniceras,  than  and some  the  in  early  Coeloceras-likt  Aveyroniceras.  forms possess  In  stage  addition,  is  more  rib density  is  persistent  much  in  greater  in  sporadic tubercles on their body chamber and final  whorl of the phragmocone.  SYNONYMS:  AGE  Indunoceras W I E D E N M A Y E R ,  1977; Cetonoceras W I E D E N M A Y E R , 1977.  A N D D I S T R I B U T I O N : Reynesocoeloceras  western  North  America,  Smith  east-central  Oregon, and also  Hillebrandt  (1973)  Reynesocoeloceras.  to Von  (1981)  cf.  Hillebrandt  Reynesocoeloceras cf. R. colubriforme Reynesocoeloceras  ranges  reports  states that  Coeloceras  is restricted  certain C.  (1981a)  the  to the Tethyan Province. In  occurence  specimens  obesum, himself  of  Reynesocoeloceras  from Chile,  probably  belong  has  described  to  by von  the  specimens  genus of  and R. cT.R. mortilleti from western South America.  from  the Ibex Zone  to its acme  i n the Davoei  (Geczy, 1976).  Reynesocoeloceras  assigned  in  cf.  R. incertum  (FUCINI,  1905)  Zone  Ill Plate 8, fig. l a , b.  cf.  *1905  Coeloceras  cf.  1971  Coeloceras  incertum  FUCINI,  (Coeloceras)  1905, p. 137, p i . 10, fig. 9-12.  incertum  incertum  FUCINI-FISCHER,  p.  110,  T e x t - f i g . 5j. cf.  1976  Coeloceras  (Reynesocoeloceras)  incertum  (Reynesocoeloceras)  cf.  FUCINI-GECZY,  p. 131, p i . 23,  fig.  4. cf.  1976  Coeloceras  C.  (R.)  incertum  FUCINI-GECZY,  p i . 23,  fig. 5. cf.  1981  Coeloceras  278,  (Reynesocoeloceras)  cf.  C.  (R.)  incertum  (FUCINI)-SMITH,  p.  p i . 15, fig. 6, 8; Text-fig. 6-15.  MATERIAL:  Three  specimens,  in calcareous  siltstone.  moderately  well  preserved as external  and internal moulds  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-90526  19  60  c70  c7.0  cl2.0  15  DESCRIPTION:  Shell is evolute, umbilicus is wide and crater-like, deeper  on the inner  whorls than on the outer whorls. Whorl section is depressed, wide rectangular to coronate. The  flanks are convex  and slightly divergent; the ventral shoulder is angular. The venter  is broad and slightly convex. Ornamentation on the inner whorls consists of short, swollen ribs  that  umbilical ribs  become seam  become  stronger  towards  the venter  i n large, rounded tubercles. narrower  and prorsiradiate,  and terminate  At. diameters and the  just  greater  tubercles  below  than  are  the succeeding  about  reduced  18 m m the somewhat  in  relation to those  o n the inner whorls. The tubercles give rise to strong, narrow secondary  ribs  slightly adorally  that  tubercle.  curve A t the  largest  as they  diameter  cross  preserved  the venter,  (D  =  31.5  and rejoin mm) there  at the opposing are  about two  112 secondaries per primary rib.  DISCUSSION: According to Geczy (1976), the depressd whorl section seen in all stages of growth, and the relatively invariable ornamentation sets species of  Reynesocoeloceras.  R.  Whereas the whorl section of most  incertum  apart from other  Reynesocoeloceras  becomes  less depressed and the venter more convex with growth, the section remains depressed in R.  incertum.  OCCURRENCE:  R.  incertum  has been reported from Hungary (Geczy, 1976) and northern  Italy (Fucini, 1905; Fischer, 1971) where it was first described. In Hungary it is found in Davoei  the Lower range of with  Zone. The Spatsizi specimens are found within the upper part of the  Dubariceras  Dubariceras  freboldi.  Smith (1981) also reports the association of  R.  incertum  freboldi.  Localities: 140. AGE:  Early Pliensbachian  (D.  freboldi  Zone).  Family DACTYLIOCERATIDAE HYATT, 1867 GENUS  TYPE SPECIES:  Ammonites  Aveyroniceras  acanthoides  PINNA and LEVI-SETT! 1971  REYNES, 1868 (p. 91, pi. 3,fig.3) by original  designation.  REMARKS: The ontogeny of  Aveyroniceras  is characterized by a change from tuberculate,  bifurcating ribs on the inner whorls to simple, dense, non-tuberculate ribs on the outer whorls.  It is this  Prodactylioceras  which  change  in morphology  that  differentiates  Aveyroniceras  from  lacks the tuberculate, bifurcating ribs on the inner whorls, but  rather, bears sporadic tubercles on all its whorls. Geczy (1976), however, points out that  113  on  some  species  of  rendering generic  Aveyroniceras  the outer  distinction between  whorls  Aveyroniceras  possess  sporadic  and Prodactylioceras  tubercles,  thereby  potentially difficult  in some cases. Aveyroniceras sporadic tubercles  SYNONYMS:  AGE  differs  from  Reynesocoeloceras  having  finer,  denser  ribs  and  on the outer whorls of some species.  Betloniceras  W I E D E N M A Y E R , 1977.  A N D DISTRIBUTION:  considered  to  Levi-Setti,  1971; Geczy,  be  has been reported  the  Aveyroniceras  Tethyan  equivalent  is restricted to  1976). It ranges from  the  of western  Innermost  Prodactylioceras  the Ibex Zone  and is  (Pinna  to the Spinatum  and  Zone. It  boundary i n Oregon (Smith, 1981)  sp. A  8, fig. 5a, b, 6.  Four individuals, poorly to moderately  external moulds i n siltstone.  Province  South America (von Hillebrandt, 1981a).  Aveyroniceras  Plate  to the Tethyan  boreal  from the L o w e r / U p p e r Pliensbachian  and from the Upper Pliensbachian  MATERIAL:  in  preserved  as fragments  of internal and  whorls not preserved.  MEASUREMENTS: SPECIMEN  D  C-90834 C-90837  DESCRIPTION:  •UD  U  WH  WW  PRHW  c80  c45  56  16  24  c40  c80  c45  56  _  _  c43  Evolute,  outer  whorls  serpenticonic  with  wide-ellipsoid  whorl  section.  114 Section shape of inner whorls unknown due to poor preservation, but comparison with what appears to be a conspecific specimen from the Queen Charlotte Islands suggests that the inner whorls (to a diameter of about 30 mm) are wide-ellipsoid to coronate. The umbilicus is wide and fairly deep as far as can be seen. The umbilical wall is high and fairly steep on the outer whorls; umbilical edge rounds gradually onto the inflated flanks. Ranks do not form a ventral shoulder; venter is broad, inflated. Ornamentation varies with growth. The innermost whorls, to a diameter of about 20 mm, are not preserved. Ribbing on the smallest preserved whorl (D =  25-30 mm)  consists of fairly stout, moderately dense ribs, most of which bear distinct ventro-lateral tubercles. These Coeloceras-like  inner whorls are succeeded by Reynesoceras-Yike middle  whorls (D = 40-50 mm) which are marked by finer, denser ribs that bear only sporadic tubercles.  Rib spacing on these whorls is somewhat  irregular and the ribs show a  tendency to occur in pairs. On the outermost preserved whorls (D>50 mm), ribbing is more consistent. The ribs are simple, non-tuberculate, prorsiradiate, and sharp. They arise at the umbilical seam and continue across the flanks and venter without a change in strength.  DISCUSSION: Although the specimens described are somewhat intermediate in nature, they are placed in the genus Aveyroniceras  rather than Reynesocoeloceras  dense ribbing and early disappearance of the Coeloceras-like characters, however, set Aveyroniceras The Coeloceras-like (D  =  due to their relatively  inner whorls. These same  sp. A apart from other species of  inner whorls of Aveyroniceras  Aveyroniceras.  sp. A disappear at a larger diameter  25-30 mm) than in most species of Aveyroniceras  (D -  10-20 mm), and the  ribbing is less dense than in the majority of species of Aveyroniceras. Aveyroniceras  sp. A is similar to A. colubriforme  and A. inaequiornatum,  both of  which are known in western North America. The variable nature of the ornament and the pairing of the ribs on the middle whorls of Avey.  sp. A is reminiscent of A.  115  inaequiornatum, spedmens  but  is  the  different  ribbing  from  A.  regular i n the Spatsizi species. outer whorls of Avey. Aveyroniceras whorl  section,  not  here  ribbing  outermost  inaequiornatum  in  preserved that  from  (Bettoniceras)" to be  sporadic  it  whorls  becomes  of  the  coarser  Spatstzi  and more  O n the other hand, the ribbing and whorl section of the  sp. A is also  considered  and  the  sp. A is similar to that of A.  to specimens  "Reynesocoeloceras  of  very similar i n rib form and density, as well South  cf.  of  America assigned  mortilleti.  conspecific  tubercles  colubriforme.  to  the  A.  South  These  by von Hillebrandt (1981) to  South  mortilleti  as i n  American forms  due to the  American forms)  differ  (which are  coarser, from  less  dense  the Spatsizi  specimens in possessing sporadic tubercles on their middle and outer whorls.  OCCURENCE:  Aveyroniceras  of Dubariceras  freboldi.  sp. A occurs  Smith (1981) reports both  to occur within the range of Dubariceras toex and Davoei  at the top of, and possibly above A. colubriforme  and A.  the range  inaequiornatum  freboldi. This range is roughly equivalant to the  Zones of northwest Europe.  Localities: 77, 80. AGE: Early Pliensbachian (D. freboldi Zone).  Aveyroniceras sp. B Plate 8, fig. 2.  MATERIAL:  A single specimen preserved as an external mould i n siltstone.  MEASUREMENTS:  DESCRIPTION:  N o t available due to the fragmentary nature of this specimen.  Shell  evolute,  whorl  section  appears  to  directly observed. Ribbing on the outermost preserved whorl  be  ellipsoidal  but cannot  be  is non-tuberculate, fine, and  116  very dense. The ribs trend slightly prorsiradiately on the lower flanks and radially on the upper  flanks,  and  appear  to  continue  unchanged  across  the  venter.  Ribs  on  the  inner  but  poor  whorl are fine and tuberculate.  DISCUSSION:  This  specimen  is  similar  to  Aveyroniceras  inaequiornatum  preservation precludes confident assignment i n this species.  OCCURRENCE: freboldi.  Aveyroniceras  Specimens  inaequiornatum  Oregon,  is found near the top of the range of  similar  to  Aveyroniceras  sp.  B  and  Dubariceras  assigned  to  A.  by Smith (1981), also occur within the range of D. freboldi.  Localities: AGE:  from  sp. B  78.  Early Pliensbachian (Z>. freboldi Zone).  Ammonite gen. et sp. indet Plate 6, fig. 6.  MATERIAL:  A single, small specimen preserved as an internal mould i n siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103306  19  8.2  43  7  -  14  DESCRIPTION: undergone  some  Shell fairly evolute, whorl lateral  compression.  section appears elliptical but the specimen  Umbilical  wall  is  low,  shallow,  umbilical  has edge  rounded; flanks convex. Ventral shoulder gendy rounded; venter inflated. Ornament  consists  of simple, straight,  edge. The ribs then terminate at about 3/4  rectiradiate of the  flank  ribs that  arise  on the  umbilical  height in sharp tubercles.  Some  117  of  the  ribs  venter  continue  faintly past  the  tubercles,  but  these  disappear  rapidly  leaving  the  featureless.  DISCUSSION:  The  small  size,  incomplete  preservation,  and  unusual  features  of  this  specimen preclude its assignment to any genus previously reported from North America. or elsewhere. assigned  The to  specimen  is  Coeloderoceras  similar  sp.?  to  by  Du  a  single  Dresnay  specimen (1963).  collected  Like  the  from  Morocco  and  Spatsizi  specimen,  Du  Dresnay's Moroccan specimen is unituberculate on the innermost whorls (although  diameters  less than 10 m m are not preserved). O n the outer whorls of D u Dresnay's specimen two or three slender secondaries arise from the outer row of tubercles According to Donovan et. Both  genera  were created  Eoderoceratidae northwest rounded  that  European  are  by  whorl  (1923) to  more  Province.  to compressed  al. (1981), Coeloderoceras is a synonym of  Spath  much  and cross the  abundant  Epideroceras section  accommodate in the  (and  certain  Mediterranean  Coeloderoceras)  and by straight,  forms  is  bituberculate  venter.  Epideroceras.  of the  region than characterized  ribs, although  family in  the  by  a  ribbing  on the inner whorls of some forms may be unituberculate. The  Spatsizi specimen  to Platypleuroceras(?) specimen  differs  secondairy  ribs  is also  similar to another  specimen  sp. by Dubar and Mouterde (1978). Dubar and Mouterde's Moroccan  from  on the  Du  Dresnay's  ventral surface  Moroccan and does  specimen not have  in true  outer whorls, although Dubar and Mouterde do state that the ventro-lateral  tubercles,  Both  Moroccan specimens  of  definition  the of  from Morocco assigned  "more  Platypleuroceras  in that  well their  as  the  the  former  bituberculate ribs  or less distinct swellings on the (as  that  posses,  lower  Spatsizi specimen)  primary ribs do not  pass  1/3  lacks  ribs on  the  i n addition to of the  flank".  violate the  generic  strongly across  the  venter. The Coeloderoceras  unsatisfactory  state  of  and Platypleuroceras  knowledge  of  the  relationship  i n Morocco is exemplified i n the  between  the  succession  of  genera forms  118  described  by  Dubai  and  Mouterde  Marking the bottom of the  (1978)  for  the  Jamesoni  Jamesoni Zone here  are  specimens  Zone  west  of  assigned to  Mougueur.  Coeloderoceras?  Una. Unfortunately, these specimens were neither described or illustrated, but it is apparent that  the  assignment  was found 13 species,  m  of  these  above  those  this  frequently  Platypleuroceras, species.  It  between  mougueurense,  new  species  seen  in  assigned  is apparent  Coeloderoceras  to  Coeloderoceras?  Platypleuroceras  however, that  specimens  to  of  Coeloderoceras  lino. was  One  collected.  Platypleuroceras  Coeloderoceras.". P.  metre  cf.  P.  as Dubar and Mouterd's Platypleuroceras^),  above  and  fairly was  there  Mouterde " . . .  1.3  a new  (1978)  note,  analogous  unambiguous  recovered exists  Platypleuroceras{1)  Platypleuroceras^),  possesses features  rotundum  and Platypleuroceras.  tenuous.  Duabar  A  from this sequence that  is  to  specimen  m  above  of  the  a morphological "grey  new zone"  The position of the Spatsizi specimen, as well within this grey zone, coupled with a lack  of  well preserved material, renders generic assignment problematic.  OCCURRENCE: was  found  in  The the  specimen  basal  part  of  Coeloderoceras  of  the  sp.?  Pliensbachian  figured (Carixian)  by  Du  section  Anoual, Morocco. Dubar and Mouterde's (1978) Moroccan specimen the  base of  the  Jamesoni Zone in a nearby  area.  The  Islands are range  to  the  Spatsizi  specimen  apparently found very low in the  of Dubariceras  Tropidoceras  Spatsizi specimen  collected  from  Pliensbachian section  freboldi. Associated genera  i n the  Queen  4.  Early Pliensbachian (L.  pinnaforme-?D.  freboldi  Zones).  Superfamily P S I L O C E R A T A C E A E H Y A T T ,  the  was  cit.)  city  of  above  found  ex  freboldi.  the  Queen  there,  well  Charlotte below  the  Charlotte collection include  and Coeloceras ( H . W . Tipper, pers. comm., 1985).  Localities: AGE:  similar  near  (op.  was found just  situ from rocks at the base of or just below the range of Dubariceras Specimens  Dresnay  1867  119  Family O X Y N O T I C E R A T B D A E H Y A T T , 1875 Genus Fanninoceras  TYPE  SPECIES  Fanninoceras  fannini  M c L E A R N , 1930  McLEARN,  1930 (p. 4, p i . 1, fig. 3), by original  designation.  REMARKS:  Involute  oxycones  depressed, becoming compressed are  short,  project  stout,  straight,  foreward  onto  with  overhanging  umbilical  wall;  early  whorls  rounded,  with angular venter on later whorls. Ribs on early whorls  and distant  the venter  O n some  forms the ribs become  with  growth. O n other  forms  has  been  by  finer,  the ribs  denser, and  disappear  with  growth, leaving the shell smooth. The European, Forsey, the  Lower  Fanninoceras Pliensbachian  1973; Donovan  genus  based  genus  Fanninoceras  (Frebold,  on its younger age (Late  It  is  found  Pliensbachian),  have  i n southern  been  BUCKMAN, have  workers 1918  argued  with  the  (Donovan  and  for the retension  of  Smith and Tipper, 1984)  its unique ontogenetic  variations i n whorl  Pacific distribution.  Argentina, and Chile. Fanninoceras specimens  however,  some  1967; von Hillebrandt, 1981a;  A N D D I S T R I B U T I O N : Fanninoceras  province.  few  Radstockiceras  et al., 1981). Others,  shape, and its restricted eastern  AGE  genus  synonymized  is characteristic  Alaska,  western  o f the eastern  British  Columbia,  Pacific  Oregon,  faunal Nevada,  is typically found i n Upper Pliensbachian strata,  recovered  from  the uppermost  Lower  Oregon (Smith, 1981).  Fanninoceras  latum M c L E A R N ,  Plate 9, fig. 1.  1930  Pliensbachian  but a  rocks  of  120  •1930  Fanninoceras  kunae var. latum  M c L E A R N , p. 5, p i . 2,  1932  Fanninoceras  kunae  var. latum  McLEARN-McLEARN,  kunae  var. latum  McLEARN-von  fig. p.  4. 78,  p i . 9,  fig.  5,  6. 1981  Fanninoceras  HILLEBRANDT,  p.  513, p i .  6, fig. 6; p i . 10, fig. 4. MATERIAL:  One specimen preserved as an external mould i n siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  GAT83-100A  28  6.5  23  cll.5  -  DESCRIPTION: species  Shell  is fairly involute  of the genus.  edge have been  The whorl  but the umbilicus is wider  section  is not preserved,  arise  about  2/3  C.18 than  near  flank  height,  then  fade  rapidly. With  denser, gently falcoid, and do not fade on the upper  and the umbilical wall and  bend  growth the ribs  latum  subspecies  F.  and  Based  on detailed  raised  to species status.  (i.e.,  studies  the genus Fanninoceras, Spatsizi  F.  kunae  by Smith  This  usage,  specimen  o f F.  Charlotte  Islands.  ribbing  than  kunae. Fanninoceras  umbilicus than F.  latum.  F.  and Tipper part  finer,  kunae  crassum  (1984) these  three  as one of three F.  kunae  varities  of a newly developed classification  have  latum).  been  scheme for  is adopted i n this study.  Queen  F.  kunae,  become  flank.  M c L e a r n (1930, 1932) originally defined Fanninoceras kunae  ribs  slightly prorsiradiately at  DISCUSSION:  The  other  of fairly coarse, strong and distant  the umbilical shoulder, trend rectiradiately,  of the  of  i n most  flattened.  Ornamentation on the inner whorls consists that  PRHW  Fanninoceras  latum latum  compares  well  with  the holotype  from the  has a wider umbilicus and slightly coarser  crassum is more  coarsely  ribbed and has a smaller  121  OCCURRENCE: Charlotte  Fanninoceras  Islands(McLearn,  latum  1932;  is found i n Upper Pliensbachian strata on the Queen  Frebold,  1967),  Alaska  Hillebrandt, 1981a). In Spatsizi it occurs i n association  (Imlay,  1981),  with Lioceratoides  and Chile (von propinquum.  This  association has also been noted i n the Queen Charlotte Islands by Frebold (1967). Localities: 60. AGE:  Late Pliensbachian ( L . propinquum  Zone).  Fanninoceras  sp.  Plate 9, fig. 2.  MATERIAL:  A single specimen poorly preserved as an internal mould i n limestone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  C-90515  c27  -  -  -  -  DESCRIPTION:  PRHW C  13  The shell is involute; whorl section is compressed. H a n k s are convex; the  venter is not exposed. Ornament consists of strong, distant ribs on the inner whorls which become denser and falcoid on the outermost preserved  DISCUSSION: but  judging  specimen  Specific assignment by its coarse  described  above  ribbing  belong  as F. latum  Arieticeras  and  Fanninoceras Leptaleoceras.  whorl.  o f this specimen is impossible due to poor preservation,  although obscurred by matrix, appears  OCCURRENCE:  finer,  sp.  is  to  i n that  Faninoceras  crassum.  It  differs  from the  its rib density is lower and its umbilicus,  narrower.  found  in  Upper  Pliensbachian  strata  containing  122 Localities: 136. AGE:  Late Pliensbachian  (F.  fannini  Zone).  Superfamily HARPOCERATACEAE NEUMAYER, 1875 Family IIILDOCERATIDAE HYATT, 1867 Subfamily ARIETICERATENAE HOWARTH, 1955 Genus  TYPE SPECIES:  Leptaleoceras  Leptaleoceras  leptum  BUCKMAN, 1918  BUCKMAN, 1918 (p. 284, pi. 26,fig.la, b) by  original designation.  REMARKS: Shells evolute; whorl section compressed, elliptical. Flanks are convex, ventral shoulder is rounded. Venter narrow, carinate; keel is flanked by narrow flat zones that become sulcate on the body chamber of some species. Ornamentation  consists of dense, slightly sinuous ribs that arise at or just above  the umbilical edge, trend more or less rectiradiately on the flanks, then fade out at the ventral  shoulder where they  project  slightly. Innermost  whorls, up to diameters not  exceeding 10 mm, are smooth. Leptaleoceras  non-sulcate  venter  Leptaleoceras  (e.g., L.  SYNONYMS:  is distinguished from observed  on  accuratum  Seguentia  by its greater rib density and the  all but the body  and  FUCINI,  Arieticeras  L.  insigne,  1931;  chamber  of some  species of  according to Alarcon (1983)).  Ugdulenia  CANTALUPPI,  1970;  Trinacrioceras  FUCINI, 1931.  AGE  AND DISTRIBUTION:  Leptaleoceras  is primarily a Tethyan form but is occasionally  found in the boreal realm (England, France, Germany). In Europe it is found in the  123  Middle  Domerian, i n association  Leptaleoceras  is  found  with  associated  Arieticeras  with  algovianum.  Arieticeras  In western  and rare  North  Fanninoceras,  America  indicating  a  Domerian age.  Leptaleoceras  cf. L.  pseudoradians  (REYNES,  1868)  Plate 9, fig. 3 - 6 .  cf.  *1868  Ammonites  pseudoradians R E Y N E S , p. 91, p i . 1, fig. 4a-c.  cf.  1934  Arieticeras  pseudoradians  (REYNES)-MONESTIER,  p. 63,  p i . 8,  fig.  61,  68,  non 62; non p i . 11, fig. 5. cf.  1957  Leptaleoceras  pseudoradians  (REYNES)-HOWARTH,  1964  Leptaleoceras  pseudoradians  (REYNES)-FREBOLD,  p. 198, p.  15,  p i . 1, fig. 1, 2. p i . 4,  non p i . 5,  fig. 4, 5. cf.  1970  Leptaleoceras  (1964 cf.  1970  pseudoradians  (REYNES)-FREBOLD,  p.  443,  pi.  2,  fig.  2  material partly refigured)  Protogrammoceras  pseudoradians ( R E Y N E S ) - M O U T E R D E  and R U G E T , p. 42,  p i . 1, fig. 6. cf.  1980  Leptaleoceras  pseudoradians  (REYNES)-WIEDENMAYER,  p.  121, p i . 23,  fig.  5, 6. cf.  1981  Leptaleoceras  cf.  L.  pseudoradians  (REYNES)-IMLAY,  p. 40, p i . 11, fig. 12,  13. 71981  Arieticeras  cf.  A.  domarense  (MENEGHINI)-IMLAY,  p. 39,  p i . 10,  fig.  15;  non fig. 1, 2, 6-14, 22. MATERIAL:  Three  fragmentary  calcareous concretion matrix.  MEASUREMENTS:  specimens  preserved  as  external  moulds  in  micritic  124  SPECIMEN  D  UD  U  WH  WW  PRHW  C-103332(P)  c25  clO  40  c9  -  c25  C-103332(Q)  38.5  17  44  cl3  C-103224  31.5  14  44  11  C - 90515(A)  39  19  49  cl3  -  C-90515(B)  c45.5  cl9  42  cl5  c5  DESCRIPTION:  Fairly evolute  forms  venter. Ornament consists of dense,  with  a compressed  whorl  26 27 25 27  section  fine sigmoidal ribs. Innermost  and a  unicarinate  whorls smooth up to a  diameter of about 6 m m .  DISCUSSION: material Imlay  from other (1981;  pseudoradians, North  see  American  Rib subspecies  density North  thus  material  specimens  on  the  accuratum  to  the  L.  cf.  North  less  pseudoradians,  densely  nevertheless,  as  well  America figured by ribbed  directly comparable  L.  Howarth  (1957)  represent  L.  is  inner  preaccuratum  Spatsizi  increasing  accuratum as  western are  not  is,  material.  diameter  American material L.  in  of  more  to  than  L.  densely  as  Frebold (1964) and  the  holotype  pseudoradians ribbed  conspecific  than  (fig.  most  of 6.2).  L. The  species  of  particularly  the  and the ribs are of the same form as those of the holotype.  L.  with  specimens  localities  are  density  comparable  Spatsizi  synonomy),  and  Leptaleoceras,  and  The  (fig.  reflected  pseudoradians recognized  pseudoradians,  that  whorls  in  although  accuratum  However, there accuratum  The  FUCINI,  the  of  is  a  tendency  preaccuratum  that  toward  reduced  rib  is not  seen  the  morphologic similarity between work  (Monestier, one  L.  as figured by Alarcon (1983, p i . 11, fig. 27-29) is  i n L. 6.2).  of  1934,  of  Monestier pi.  Monestier's  8,  specimens  Howarth offered  (1983), in turn, assigned the specimen to L.  fig.  accuratum.  no  (1934) 61,  who  62,  (pi.  alternative  L.  68).  8,  fig.  in  pseudoradians figured  three  Subsequently, 62)  did not  assignment  Alarcon  3634 32^ fr O  30  E  28H  ^ <  26  O)  5  CC >  22]  •  Leptaleoceras pseudoradians (Reynes. 1868)  A  L. p s e u d o r a d i a n s (Frebold, 1 9 7 0 )  •  L. cf. L. p s e u d o r a d i a n s (Imlay, 1 9 8 1 )  A  L. cf. L. p s e u d o r a d i a n s ( t h i s s t u d y )  o  L. a c c u r a t u m p r e a c c u r a t u m  •  L. a c c u r a t u m a c c u r a t u m  20-  <  I  fX 0.  18"  16-  —i— 11  13  —i 15 15  1— 1 7 17  19  i  21  23  UMBILICAL DIAMETER (mm) FIGURE  6.2  1——i— 25  27  G r a p h c o m p a r i n g r i b density between Leptaleoceras pseudoradians and Leptaleoceras accuratum. Points for specimens o f L. cf. L. pseudoradians f r o m the thesis m a p area occupy a f i e l d between the type specimen o f L. pseudoradians (Reynes, 1868) a n d L. accuratum accuratum illustrated by A l a r c o n (1983). Points for specimens of L . accuratum preaccuratum ( A l a r c o n , 1983) o v e r l a p the field o f L. cf. L. pseudoradians, but show a trend towards decreasing r i b density w i t h diameter.  Alarcon, 1983  126  OCCURRENCE: France,  Italy,  L. pseudoradians  is reported  Switzerland and Portugal. This  the Lower Pliensbachian genus  Dayiceras  been  connection  a  Pliensbachian  allowed has  marine  limited migration between  been  from the Dorset  coast of England, southern  distribution is similar to that  described for  and supports the hypothesis that there may have between  provinces.  the  Boreal  In western  North  and Tethyan America L.  found i n northern British Columbia, southern Y u k o n , and southern  realm  pseudoradians Alaska. The  Spatsizi specimens  of L. cf. L. pseudoradians are found i n the same -concretion  L.  algovianum,  accuratum,  A.  A.  cf.  A.  ruthenense  and rare  that  bed with  Fanninoceras.  Localities: 24, 26-28, 81, 107, 131, 132, 136. AGE:  Late Pliensbachian (F. fannini  Genus  TYPE  SPECIES:  REMARKS: either  Ammonites  Zone).  Arieticeras  algovianus  Shell evolute, whorl  OPPEL,  section  by shallow sulci or flat zones.  moderately  sinuous ribs  O P P E L , 1862  1862, by original designation.  elliptical to quadrate.  Ornamentation  of moderately  dense  consists  to distant  Venter  unicarinate,  flanked  of strong, simple, straight to  spacing. Ribbing may lose  relief  and become striate o n the outer whorls of large, adult specimens. Arieticeras commonly  sulcate  differs venter.  from  Leptaleoceras  Oregonites  by  its  WIEDENMAYER  coarser, is distinct  less  dense  from  ribbing and  Arieticeras  i n its  more irregular, often paired ribbing and generally more depressed whorl section.  SYNONYMS:  Seguenziceras  LEVI,  1896;  Meneghinia  FUCINI,  1931;  Emaciaticeras  F U C I N I , 1931.  AGE  A N D D I S T R I B U T I O N : Arieticeras  is a Tethyan  form, commonly found i n southern  127  Europe  and north Africa. It has been  northwestern  British  Columbia,  reported  southern  from South  Yukon  (Frebold,  America (Hillebrandt, 1981b), 1964, 1970),  southern  Alaska  (Imlay, 1981) and from the western U . S . (Smith, 1981; Imlay, 1968). Arieticeras Algovianum  Zone  is  characteristic  of  the  Domerian,  and is  most  abundant  i n the  o f the Tethyan region (roughly equivalent to the Margaritatus  Zone of  the N . W . European Province; see Wiedenmayer (1980) and Alarcon (1983)).  Arieticeras  algovianum  (REYNES,  1868)  Plate 9, fig. 7 - 1 1 .  *1853  Ammonites  radians  amalthei  OPPEL,  p. 51, p i . 3, fig. 1.  1862  Amm. algovianus  O P P E L , p. 137.  1868  Amm.  algovianus  OPPEL-REYNES,  1885  Amm.  radians  1899  Arieticeras  algovianum  ( O P P E L ) - F U C I N I , p. 175, p i . 24, fig. 1.  1908  Hildoceras  algovianum  ( O P P E L ) - F U C I N I , p. 54, p i . 2, fig. 5, 6.  1909  Segueniceras algovianum  ( O P P E L ) - R O S E N B E R G , p. 288, p i . 14, fig. 18-20.  1931  Arieticeras  almoetianum  FUCINI,  1934  Arieticeras  algovianum  p.  crassitesta Q U E N S T E D T ,  92, pi. 2, fig. 1. p. 341, p i . 42, fig. 43, 45.  p. 105, p i . 8, fig. 1; non fig. 2-4.  (OPPEL)-MONESTIER,  p.  55,  p i . 7,  fig.  1-3,  non  fig. 4. 1934  Arieticeras  19; 1964  panned  GEMMELLARO-MONESTIER,  p. 66, p i . 7,  fig.  15,  16,  p i . 9, fig. 17.  Arieticeras  algovianum  (OPPEL)-FREBOLD,  p.  13, p i . 3,  fig.  4,  5;  p i . 4,  fig.  3; p i .  fig. 2. 1964  Arieticeras  cf.  A.  algovianum  (OPPEL)-FREBOLD,  p. 13, p i . 3,  5, fig. 3, non fig. 2. 1968  Arieticeras  cf.  A. algovianun ( O P P E L ) - I M L A Y ,  p. C34, p i . 4,  fig.  1-8.  128  1968  Arieticeras  cf.  A.  domarense  (MENEGHINI)-IMLAY,  p.  C33,  p i . 4,  fig.  9-12. 1977  Arieticeras  algovianum  1980  Arieticeras  algovianum  (OPPEL)-WIEDENMAYER,  p. 86, p i . 16, fig. 15, 16.  (OPPEL)-WIEDENMAYER,  p.  109,  p i . 17,  fig. 19,  20. 1981  Arieticeras  cf. A. algovianun  1981  Arieticeras  cf.  A.  ( O P P E L ) - I M L A Y , p. 40, p i . 10, fig. 16-20.  domarense  (MENEGHINI)-IMLAY  p.  39,  p i . 10,  fig.  1,  2, 9, 10, non fig. 6-8, 11-15, 22. 1981  Arieticeras  cf.  A.  algovianum  1983  Arieticeras  algovianum  (OPPEL)-SMITH,  (OPPEL)-ALARCON,  p. 292, p i . 17, fig. 1, 2.  p. 226, p i . 10,  fig.  1-6.  Other synonyms, see Alarcon, 1983, and Smith, 1981.  MATERIAL:  Thirtv  specimens  preserved  as  fragmental  external  and  internal  moulds  concretion matrix and siltstone.  calcareous  MEASUREMENTS: SPECIMEN  D  UD-  U  WH  C-103223(A)  c65  30  46  -  C-103223(B)  37  15  41  -  -  C-103328  43  19  44  cl4  -  17  C-103111  55  24  43  c20  -  19  C-90915(A)  -  -  -  19  10.5  -  C-90515(B)  38  17  45  12  6.5  18  C-90915(C)  c70  33  47  cl8  cl9  22  DESCRIPTION: shallow;  Shell  umbilical  edge  evolute.  whorl  rounded.  section  Flanks  are  ogival  to  slightly  WW  rectangular. convex,  PRHW 22 17  Umbilical  parallel;  ventral  wall  :  shoulder  129  abruptly rounded. Venter bears a high keel bordered by flat zones or shallow sulci which, on internal moulds, appear deeper and wider than on external moulds. Ornamentation consists is equal to or just greater  of strong, slightly to moderately sinuous ribs whose spacing  than their width. The ribs have an overall, slightly rursiradiate  trend. In general, rib density decreases, whereas arise  on the  height,  the  umbilical edge ribs  curve  where they project  where  gently  they  sinuousity increases  with growth. The  trend prorsiradiately. A t about  backward  and  adorally for a distance  trend  about  rursiradiately to  equal to one  1/3  the  of the  ventral  inter-rib space,  ribs flank  shoulder then  fade  algovianum  and  along the sulci.  DISCUSSION: A.  cf.  The cf.  The  Spatsizi material  A. algovianum  tends  to  have  specimens Spatsizi  a  are  wider  assigned  " . . .  with  specimens  of  A.  also similar to  Imlay's  (1968, 1981)  figured  specimens  of  A.  from Alaska and the western United States, except that Imlay's material whorl  section  by Imlay (op.  specimens  domarense  well  from northwest British Columbia as figured by Frebold (1964, 1970).  Spatsizi specimens A. algovianum  matches  of  A.  cit.)  to  algovianum.  occurs with (A.  cf.  and A.  Imlay A.  coarser  ribbing. In  cf.  domarense appear  A.  himself  algovianum)  states  that  addition, some  of  the  conspecific to  the  because  his  A.  cf.  A.  at many localities and has the same  stratigraphic range, it may be a variant" (1969, p. C34). Wiedenmayer domarense into the by  forms  with  a  new genus depressed  often paired at the of  the  differ  specimens markedly  (1980) placed  A.  whorl  from  cf.  the  (1968)  A.  cf.  A.  Oregonites W I E D E N M A Y E R  base of the of  Imlay's  A.  section  flanks.  and coarser  algovianum  and  (1980), which  ribs  is  A.  cf.  characterized  of irregular relief which  Except for the compressed whorl section of  algovianum,  "conventional"  Imlay's definition  (1968) of  material  A.  does  algovianum  A.  not and  are some  seem is  to here  considered a morphological variant of that species. The question as to whether or not the genus  Oregonites  is  valid,  or  i f the  specimens  assigned  to  it  (Wiedenmayer,  1980)  are,  130  instead,  variants  Canavaria, therefore,  of  has been  European  raised  genera  Arieticeras,  by Alarcon (1983).  Fontanelliceras,  The status  Fuciniceras,  o f the genus  or  Oregonites is,  unsatisfactory, and requires further investigation.  OCCURRENCE: from  the  Morocco,  Germany.  A. algovianum Spain,  In North  Columbia,  and  is common  southern America  southern  France, it  Italy,  occurs  Yukon  i n the Domerian  and  It is reported  Switzerland, and as far north  i n Mexico, is  of Tethys.  found  the western associated  United  with  as southern  States,  British  Leptaleoceras  and  Fanninoceras.  Localities: 24, 26-28, 66, 131, 132. AGE:  Late Pliensbachian (F. fannini  Arieticeras  cf.  Zone).  A. ruthenense  (REYNES,  1868)  Plate 10; fig. 1, 2.  cf. non  *1868 1909  Ammonites  ruthenense R E Y N E S , p. 94, p i . 2, fig. 4 a - c .  Seguenziceras  ruthenense ( R E Y N E S ) emend. M g h - R O S E N B E R G , p. 291, p i .  15, fig. 2a-c. cf.  1934  Arieticeras  ruthenense  (REYNES)  var. t y p i q u e - M O N E S T I E R , p. 59, p i . 8,  fig. 2, 4, 5, non fig. 1, 12, 19. cf.  1934  Arieticeras  ruthenense  (REYNES)  var. meneghiniana- M O N E S T I E R ,  p. 59, p i .  8, fig. 39, 40, non fig. 38; non p i . 11, fig. 2. non  1964  Arieticeras  aff.  ( = Leptaleoceras cf.  1968  Fuciniceras  cf.  A. ruthenense  (REYNES)-FREBOLD,  p. 14, p i . 4, fig. 3, 4  sp.) F.  acutidorsatum  KOVACS-IMLAY,  p.  C 4 1 , p i . 7,  fig.  22,  p.  85,  fig.  17;  24. cf.  1977  Arieticeras  ruthenense  (REYNES)-WIEDENMAYER,  p i . 16,  131  pi. 17, fig. 3. cf.  1980  Arieticeras  ruthenense  (REYNES)-WIEDENMAYER,  p.  115,  pi.  20,  fig.  21-24; p i . 21, fig. 1, 2. Other synonyms, see Wiedenmayer, 1977. MATERIAL:  N i n e specimens,  moulds i n calcareous  poorly to moderately  well preserved as external  and internal  concretion matrix.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103110  47  17  36  15  c6  21  C-103120  50  21  42  19  c7.5  23  C-103328  c37  cl4.5  39  13  8  c21  whorl  section  DESCRIPTION: umbilical  Shell  edge  rounds  distinctly carinate;  edge,  onto  convex  flanks.  consists trend  of simple,  rectiradiately  straight to  between  Ventral  Umbilical  shoulder  specimens;  both  fine  to slightly  slightly  slightly at the ventral shoulder. R i b strength or  ellipsoid.  wall  rounded,  low, shallow; venter  convex,  arise  on the  keel bordered by slightly depressed sulci.  Ornament umbilical  evolute,  sinuous  rursiradiately  ribs  on the  that flanks,  and  may vary with growth on a single  to moderately  coarse ribs  are observed  project  specimen  on the Spatsizi  material.  DISCUSSION: relationship This  According to Alarcon (1983), the status of the species ruthenense, and its  to other  problem  is  species  reflected  i n the genera in  the  Arieticeras  complexity  and Leptaleoceras  and length  of  the  is i n question.  synonymy  for  A.  ruthenense i n Wiedenmayer (1977). Alarcon (op. cit.) points out the morphologic similarity between forms  Leptaleoceras  are best  accuratum  considered  and A. ruthenense  as end members  and concludes  of a continuous  that perhaps  morphologic  series.  the two In this  132  study cf.  A. ruthenense is retained,  as specimens from the Spatsizi collection  A. ruthenense possess generally  less compressed  whorl section,  coarser, straighter,  than  has coarser, more sinuous ribs than  OCCURRENCE: and  north  previous  Africa.  report  Its  of  been  Wiedenmayer  also  as  Spatsizi,  distribution  found  i n western  only  i n the Tethyan  North  America  questioned  (op. cit.; see  cf.  by certain  Wiedenmayer  F. acutidorsatum, to  A. ruthenense is  Columbia  specimens from the western  found  be  conspecific  associated  with  region  is poorly  British  considered  ribs,  and a  to L. accuratum. A. algovianum  A. ruthenense i n northwestern  Fuciniceras  A. cf.  assigned  spaced  to A.  A. cf. A. ruthenense.  A. ruthenense has been  subsequently  (1968)  specimens  and less densely  assigned  of  Europe  documented.  (Frebold,  A  1964) has  synonymy),  although  U . S . , reported  by Imlay  with  L. cf.  A. ruthenense. In  L. pseudoradians, A.  algovianum, and rare Fanninoceras. Localities: AGE:  26, 27, 106-108.  Late Pliensbachian (F. fannini Zone).  Subfamily H A R P O C E R A T I N A E  NEUMAYR,  1875  Genus Lioceratoides S P A T H , 1919  TYPE  SPECIES;  Lioceras? grecoi F U C I N I ,  1900  (p.  65,  p i . 11,  fig.  4)  by  original  designation.  REMARKS:  Shell  midvolute  to  involute,  narrow and bears a keel (indistinct zones Flanks  inclined  towards,  are convex,  whorl  section  ellipsoid  to  ogival.  Venter  on some species) and is flanked by two narrow  and separated  from  the  flanks  by an obtuse  umbilical edge is rounded, and the umbilical slope  ventral  is flat  shoulder.  ranges from gentle  133  to moderately  steep.  Ornamentation is variable. In general, it consists of falciform ribs that arise on, or just  above  the umbilical seam.  The ribs attain  their  maximum relief at 1/3  the whorl height where they curve adapically. In most species  or 1/2  of  the ribs weaken above the  inflection point and often furcate or are separated by intercalary ribs. The ribs then swing forward  at  about  Ornamentation the  2/3  of  appears  the  whorl  on the inner  inner whorls tends  height  and fade  out along  whorls at a diameter  the  of about  ventral  shoulder.  5 m m . Ribbing on  to be less sinuous than the strongly projecting, falciform ribs on  the outer whorls. For preserved  the on  part,  internal  Lioceratoides angionum  most  show  moulds  a  FUCINI,  ornamentation (Alarcon,  progressive  L.  silvestrii  of  Lioceratoides  is  1983).  Moreover,  many  fading  of  FUCINI,  ornament L.  with  naxosianum  faint,  particularly  of  the  growth  (for  FUCINI,  L.  when  specimens  of  example,  L.  naumachensis  F U C I N I , L. lorioli B E T T O N I , and L. expatus G E M M E L L A R O ) . Neolioceratoides  has been synonymized with  Lioceratoides  by Donovan et al. (1981),  but is considered a separate genus by Wiedenmayer (1980) and Alarcon (1983). According to  the  proponents  carinate-bisulcate and  simple  of  Neolioceratoides,  it  differs  from  Lioceratoides  in  having  venter, a more angular ventral shoulder, a less compressed whorl  (non-furcating)  ribs  that  arise  higher  on  the  flanks  than  a  section,  those  of  Lioceratoides.  Fieldingiceras confused fig.  12,  with  Lioceratoides;  13)  Lioceratoides,  SYNONYMS:  (formerly Fieldingia  as  C A N T A L U P P I ) includes some  for example,  Praelioceras  the specimens  pseudofieldingi.  and has fewer, straighter ribs.  Nagaticeras  MATSUMOTO,  1947.  forms that may be  figured by Fucini  Fieldingiceras  is  more  (1930, p i . 6, evolute  than  134  AGE  A N D D I S T R I B I JTTON:  found i n the also  found  Lioceratoides  Iberian Penninsula,  in the  Morocco,  Western Cordillera  is characteristic of the  Alps  of North  It  is  of northern Italy, and Japan. It  is  America.  the  In the  Tethyan Realm.  Mediterranean region it  ranges from the Domerian to the basal Toarcian.  Lioceratoides  propinquum  (WHITEAVES,  1884)  Plate 10, fig. 3-9.  •1884  Schloenbachia  propinquia W H I T E A V E S , p. 274, p i . 33, fig. 2, 2a.  1930  Harpoceras  propinquum  1932  H. propinquum  ( W H . ) - M c L E A R N , p. 66, p i . 6, fig. 1-4;  1944  H. propinquum  (WH.)-SHIMMER  1964  H.  propinquum  ( W H . ) - M c M L E A R N , p. 4. p i . 7, fig. 3.  and S H R O C K , p i . 240, fig. 13,14.  (WH.)- FREBOLD,  pi.  8,  fig.  4,5,7  (McLearn's  (1932)  material refigured). 71966  Ovaticeras facetum  71968  O. facetum  71968  O. propinquum  71968  Protogrammoceras? fig.  cf.  and R E P I N , p. 45, p i . 1, fig. 4,5,8.  P. and R - R E P I N , p 45, p i . 46, fig. 1,2,4,5. ( W H . ) - R E P I N , p. 116, p i . 44, fig. 1; p i . 45, fig. 1. cf.  P.  pseudofieldingi  (FUCINI)-IMLAY,  p.  C40,  p i . 7,  5-7.  71971  Tiltoniceras  71974  T. propinquum  1980  POLBOTKO  Lioceratoides  propinquum  (WH.)-DAGIS,  p i . 4,  fig.  4,5.  ( W H . ) - D A G I S , p. 21, pi. 1, fig. 1-4;  p i . 2, fig. 1.  expatus ( G E M M E L L A R O ) - W I E D E N M A Y E R , p.  90,  pi.  13,  fig.  9,10. 1981  MATERIAL:  Tiltoniceras  propinquum  (WH.)-SMITH,  Ninety nine specimens, poorly  p.  316,  p i . 19,  fig.  1-6.  preserved as external and internal  moulds in  135  calcareous  to non-calcareous  siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103224(A)  60  19  32  25  -  -  C-103224(B)  39  12  32  13  GAT83-100A  32  8  23  14  C-103203(A)  33  9  28  15  -  -  C-103204(C)  -  -  -  22  c8  C-103204(D)  33  10  30  13  -  -  C-103204(E)  49  14  29  20  -  -  C-103332  c46  ell  24  19  —  —  DESCRIPTION:  Shell  Umbilical  is  slope  flanks. The  is  low  venter  involute  and  to  gentle,  midvolute;  umbilical  is narrow and bears a keel  whorl  edge  section  rounds  compressed,  evenly  onto  ellipsoid.  slightly  convex  flanked by two flat bands sloping towards  the flanks; ventral shoulder is rounded. Ornament diameter) shell  are  is  not  marked  primary  ribs  prorsiradiate  varies  on  through  observed by  an  the  primaries  in  this  early  lower give  ontogony.  collection.  stage 1/3  rise  of to  backwards  from the  imparting  a falcoid appearance to the  inserted between at  the  point  of  top of the  The  of the two  innermost  From  moderately flank. or  primaries, then  about  at  about  of  (less 25  the  flank  the  than  mm  somewhat  secondary  broad  mm  but  these  ribs  the faint  slightly  which  approach  secondary  10  diameter  mid-flank,  arc adorally as they  ribbing. Some of  1/3  to  below  slender  those arising from the primary ribs. The furcation,  10  distant,  Just  three  whorls  the  ribs appear  bend venter, to  be  relief of the ribbing is greatest height.  The  ribs  fade  near  the  136  ventral shoulder. W i t h  growth the ribbing becomes  fainter and the slender secondaries no  longer join below m i d - f l a n k , but rather, they become the umbilical  edge. A t diameters greater  faciculate  and fade out just  above  than about 35 m m , ribbing has almost completly  faded, leaving the flanks either smooth or marked with faint, densely spaced, falcoid lirae.  DISCUSSION:  Mounting unpublished evidence, including stratigraphic data from the Spatsizi  area,  that  and  indicates believed  Domerian.  to  Lioceratoides  be  propinquum,  of Toarcian  age,  previously placed  first  appears  i n the genus  Tiltoniceras  i n , and may be  restricted  to the  Ammonites from boulders i n the Maude Formation (Queen  Charlotte  Islands)  have recently been examined by M . K . Howarth (written communication to H . W . Tipper, 1980)  and were  specimens possibly  of  found to contain  the  belonging  Amaltheus  Late to  has been  Pliensbachian  the  Spatsizi,  genus  of Lioceratoides  genus  Fanninoceras  Protogrammoceras.  found associated  W . Tipper, pers. comm., In  specimens  with  propinquum and  "Harpoceras"-\\kt  Subsequently,  L. propinquum  a  single  propinquum  and  Protogrammoceras  found  the  is  found  occurrences  of  L.  between  propinquum  L.  specimen  paltum  and L. propinquum  propinquum  forms of  1985).  Lioceratoides  association  with  i n the Maude Formation ( H .  found i n the same rock (pi. 10, fig. 8). Fanninoceras in  associated  with in  one strata  propinquum  another, below  and  the  all indicate  at  first a  Late  Plateau  appearance  of  Pliensbachian  have  been  have also been  section,  Lioceratoides  Dactylioceras.  These  age. T h e relationship  and the Toarcian/Pliensbachian boundary is discussed  further i n  the biochronology section.  OCCURRENCE:  L. propinquum  is abundant at its type locality i n the M a u d e Formation  on the Queen Charlotte Islands, and is also found i n Oregon, Nevada (Smith, 1981), and possibly  California  (Imlay,  1968; see synonomy). T o date,  L.  propinquum  found i n the Mediterranean area, although similar forms have been  figured  has not been (for example,  137  Lioceratoides  expatus ( G E M M . )  i n Wiedenmayer,  1980,  doubt as to whether the specimens  of Tiltoniceras  b;  North  1974)  Smith,  are  conspecific  pers. comm.,  propinquum  with  the  1984), thus  the  propinquum  American material  extension  fig.  of  the  9,10). There  is  some  from Siberia (Dagis, 1971a, (M. K.  geographic  Howarth to  range  of  P.  L.  Lioceratoides  to the Soviet arctic is problematic.  Localities: 55, 56, 60, 132, AGE:  pi. 13,  Late Pliensbachian (L.  135.  propinquum  Zone).  Lioceratiodes  sp.  A  Plate 11, fig. 1.  MATERIAL:  A single specimen, poorly preserved as an external mould i n siltstone.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103204(A)  51.5  15  29  21  -  19  DESCRIPTION: appears  to be  Shell is midvolte, expansion moderate; elliptical. The  venter  bears a  whorl section poorly preserved  distinct keel that  appears  two shallow sulci. The umbilicus is shallow and the umbilical slope Ornamentation The  ribs  foreward  arise and  consists  at about 2/5 project  of  rather  the  height  of the  short  distance  adorally  a  broad, rounded, falcoid flank, before  ribs  to be  but  flanked by  gentle. of moderate  density.  gently bend adapically, then swing fading  completly just  below  the  of this specimen suggest that it may have affinities to  the  ventral shoulder.  DISCUSSION: genus  Certain features  Nedioceratoides  although  not  well  as defined by Wiedenmayer (1980) and Alarcon (1983). The preserved,  appears  to  be  carinate-bilsulcate,  and  the  ribs  are  venter, simple  138  (i.e., do not furcate as is usual i n Lioceratoides). specimen, together would  make  However, incomplete preservation of the  with the fact that it is the only one o f its kind  its assignment  to Neolioceratoides,  a somewhat  found i n the area,  controvercial genus  heretofore  unknown i n North America, tenuous at best  OCCURRENCE: propinquum  This  and L.  specimen  of  Lioceratoides  sp.  A  is  found  associated  with  L.  sp. B.  Localities: 56. AGE:  Late Pliensbachian (L. propinquum  Zone).  Lioceratoides  sp. B  Plate 11, fig. 2.  MATERIAL:  A single specimen, poorly preserved i n siltstone  as an external mould  with  part of an internal mould.  MEASUREMENTS: SPECIMEN  D  UD  U  WH  WW  PRHW  C-103204(B)  c43  cl3  30  cl8  -  ell  DESCRIPTION:  Although  been  Shell  ellipsoidal.  the specimen  is distorted, the whorl  is midvolute, umbilical  slope  is gentle  section  appears  and the umbilical  to  have  edge is  rounded. The venter is distinctly carinate and possibly bisulcate. Ornament consists of irregularly spaced, falcoid ribs of variable relief (possibly due to preservation) that arise above the umbilical shoulder, gain their full relief at midflank, gently flex adorally, then fade below the ventral shoulder.  DISCUSSION:  Lioceratoides  sp.  B,  like  Lioceratoides  sp.  A,  appears  to  have  a  139 carinate-bisulcate venter and the simple ribs characteristic of  again, a lack of evidence would make assignment to Nedioceratoides  OCCURRENCE: Lioceratoides  The specimen  propinquum  and  of  Lioceratoides  Lioceratoides  sp. B  but here  Nedioceratoides,  problematic.  is found  associated with  sp. A.  Localities: 56. AGE: Late Pliensbachian (L.  Genus  TYPE  SPECTES:  Zone).  propinquum  Grammoceras  Protogrammoceras  bassanii  SPATH, 1913  FUCINI, 1900 (p. 46, pi. 10,fig.6) by  subsequent designation (Spath, 1919).  REMARKS:  is comprised of midvolute to involute, compressed forms  Protogrammoceras  characterized by dense to very dense,flat-topped,falcoid ribs that project strongly onto the venter. The umbilical wall is low and may be steep to shallow. The venter bears a high keel. Protogrammoceras Fuciniceras;  is often confused with similar forms belonging to the genus  the two genera can be distinguished by the fact that the ribs are more  strongly projecting in  SYNONYMS:  Protogrammoceras  Paltarpiles  BUCKMAN, 1927; Neoprotogrammoceras  than in  BUCKMAN, 1922;  Bassaniceras  Fuciniceras.  Argutarpites  FUCINI, 1923;  BUCKMAN, 1923;  Eoprotogrammoceras  Platyharpites  CANTALUPPI, 1970;  CANTALUPPI, 1970.  AGE AND DISTRIBUTION:  Protogrammoceras  was most abundant in the Tethyan region  but was also common in many other parts of the world (Howarth, 1973b; Srnith, 1981).  140  Protogrammoceras (Hirano, 1968,  1971),  1981;  Siberia  presence  documented  Eastern  and  (Fischer,  Platyharpites,  the  representitives  of  The  recognition  allowed  for  describes  Kalacheva,  Protogrammoceras  brief  i n the  (Maubeuge,  1975).  creating  By  work  of  Paltarpites detailed  as  western  North  America  the  sparce  of  genera  (1922,  effectively  masked  synonym  on  Arieticeras  Liassic  sea  and  during  Fuciniceras, the  migrated  to  Howarth, 1973a),  Rioult,  Carixian Ibex Zone,  be  genus  Jurassic basin during the Domerian Margaritatus  Protogrammoceras  northwest  Paltarpites  1934  Polyplectus  kurrianus  1964  Harpoceras  cf.  fig. 1970  paltus B U C K M A N ,  H.  by  and  European  Howarth (1973a)  worked out to  during  the the  Tethys  subsequently  to  to the  Smith Liassic  (1981) seas  of  Domerian and in the company  the  South-German  Northwest-German  fig.  BUCKMAN,  1922  3-5.  p i . 362a, b.  OPPEL-MONESTIER,  exaratum ( Y O U N G  p.  90,  p i . 5,  fig.  23.  and B I R D ) - F R E B O L D , p. 16, p i . 6,  1-5.  Paltarpites  and  Zone.  paltum  Plate 11,  •1922  northern  and  1964),  Argutarpites,  these  from Tethys  of that  from  been  their paleobiogeographic implications.  histories  there  and  Protogrammoceras  Protogrammoceras  appearance  1927;  Paltarpites,  1923)  of  1923,  Maubeuge  Buckman  a  1922,  basal Toarcian. Fischer (1975) gives an account of how Protogrammoceras, of  (Imlay,  Northwest European Province has  1948;  paleobiogeographic  excursions  England resulted in the  and  from England (Buckman,  Protogrammoceras of  1980),  Luxembourg  early  more  how  of  and  Smith, 1981).  i n reports  France  Germany  (Sey  Frebold, 1970;  The well  has been reported from various points i n the c i r c u m - Pacific; from Japan  paltus B U C K M A N - F R E B O L D ,  p.  443,  p i . 14,  fig.  5-7.  141  1971  Paltarpites  paltus B U C K M A N - H I R A N O , p. 115,  71977  Paltarpites  paltus ( B U C K M A N ) - W I E D E N M A Y E R , p. 94, p i . 17, fig. 10.  1981  Protogrammoceras  cf.  P.  paltum  p i . 19,  fig.  (BUCKMAN)-IMLAY,  p.  7,  8.  41,  pi.  12,  fig.  11, 12. 1983  Protogrammoceras  paltum  (BUCKMAN)-HALL  and H O W A R T H ,  p. 1470,  fig. 3 a - d . MATERIAL:  Approximately twenty  five  specimens  external moulds i n siltstone and calcareous  poorly to moderately well  preserved as  siltstone.  MEASUREMENTS; SPECIMEN  D  UD  U  WH  WW  PRHW  C-103204(P)  c95  c27  28  c41  -  c50  C-103204(PP)  c68  cl8  26  c30  -  c46  DESCRIPTION:  Shell compressed,  fairly involute; whorl section not preserved but appears  to be ellipsoid or ogi val. Umbilical  wall is convex, low, moderately steep;  umbilical edge  rounded. Flanks are convex, ventral shoulder rounded; venter is inflated and bears a high keel. Ornament consists  o f dense,  falcoid, flat-topped ribs that are strongly projected on  the venter. The width of the ribs varies slightly with growth; i n general, the ribs narrower at larger  DISCUSSION:  Buckman,  diameters.  Protogrammoceras  1922)  has  a  paltum  variable  (originally  morphology  holotype (pi. 362a) and paratype (pi. 362b) less  involute  and has  a  more  paratype. The Spatsizi specimens Buckman's  become  holotype,  but  are  variable  as  evidenced  figured  involute,  have as  to  by  Paltarpites  differences  paltus  seen  by  i n the  by Buckman (1922). The holotype is  (and generally  of P. paltum more  assigned  greater)  a comparable is  Buckman's  rib density  than  the  rib density to that of paratype.  The  variable  142  morphology of  P. paltum has also been observed  and Howarth, 1983) further  states  equivalent  and from British Columbia and the  that  P.  in collections  the  argutum  morphological is  bridged  gap  by  between  P.  transitional  from Arctic Canada  Y u k o n by paltum  forms.  Frebold  and  The  the  Spatsizi  (Hall  (1970), who  stratigraphically specimens  may  represent such transitional forms in that their rib density, while generally greater than that of most  of the  specimens  of P. paltum  listed in the  synonomy, is less than  that of  P.  argutum.  OCCURRENCE: common 1981),  P.  paltum  is  occurs the  the  Canadian  is  found  Arctic  associated  below the  Taku  species,  Archepelago  area  (Frebold,  have  of  with  (Hall  and the  and  also  the  arctic  British  a  propinquum  specimens  of  paltum  from  on  the  Northwest  (Maubeuge  and  biostratigraphic  European  Rioult,  studies  the  Alpine  Pliensbachian  and  of  age,  North America.  Mediterranean  and  as  discussed  Province,  1964), the  (1973a) proposed the P. paltum subzone In  is  the  western  1981). In Spatsizi, Fanninoceras,  is  found  age.  to  the  associated  P. and In  with  Hall  and Howarth  Upper  Pliensbachian  Zone).  Luxembourg Based  it  a Late Pliensbachian age.  Pliensbachian  P.  and  rare  paltum  H a l l and Howarth (1983) point out that P. paltum Specimens  1983),  and  suggesting  Late  aspect;  (Hirano, 1971), Alaska (Imlay,  Howarth,  Columbia, P.  indicating  Tethyan  United States (Smith,  Lioceratoides  northern  1970),  assigned  (Margaritatus  1970)  primarily of  from Japan  first appearance of Dactylioceras,  River  Amaltheus (1983)  widespread  in Europe and has also been reported  Cordillera of Canada (Frebold, paltum  a  are  above,  lowest  succession  as the  region  notably  of P.  has  a diachronous distribution.  England  Toarcian on  the  in  (Howarth, 1973) age  Yorkshire  lowest division of the Europe, paltum  however, is  of  P.  Late  (Howarth, coast,  1973).  Howarth  Tenuicostaum paltum  is  Pliensbachian  and  Zone.  of age  Late in  Localities: AGE:  55, 56, 60, 83, 131,  135.  Late Pliensbachian ( L . propinquum  Zone).  7. S U M M A R Y The from  emphasis  the thesis  of this  map area  study  of  was to document  and nearby  including the lithostratigraphy, the  about  localities,  the Pliensbachian  and to  fill  of north-central  the need  British  1970) on Pliensbachian ammonites  Columbia. Previous  from north-central  1983;  classification  Smith,  scheme  1981;  Imlay,  1981).  for Liassic ammonites  1981),  and refinements  Taylor  et al., 1984) and biochronology  i n theories  concerning  the twenty  first  time  five  from  Luningericeras  pinnaforme,  R.  Lioceratoides  incertum,  indeterminate specimens America.  specimen  of Dayiceras Specimens  (Donovan  the tectonic  (Smith,  species  Stikina.  Metaderoceras sp.  A  described  since  1970,  (including  on  of Aveyroniceras  Acanthopleuroceras,  unrestricted  Metaderoceras  occurrence,  and  faunas  revisions  of  1973; Donovan  paleobiogeography  1981) necessitated  examined,  These silviesi,  and  sp.  page  sp. represent the  of the ammonites  evolution of  1977, 1980; Geczy, 1976;  from  include  the  et al.,  (Ziegler,  a second  of them  Dayiceras  Metaderoceras  B,  sp.,  Fanninoceras  116  first  many  1981;  look  at the  (ammonite  gen.  known specimens  Spatsizi  described  herein  Tropidoceras, others  and latum,  Uptonia  Reynesocoeloceras  et  and  sp.  the  o f that genus  cf.  single  indet).  The  i n North  to material  affinity,  although  Protogrammoceras) Dubariceras  are  freboldi,  silviesi) are endemic to the East Pacific faunal realm. N o Boreal  144  sp.,  from  Prodactylioceras.  are o f Tethyan  (Fanninoceras  sp.,  may be conspecific  Uptonia,  are recorded for  latum,  northern Stikina previously described by Frebold (1964, 1970) as Most  is, before  of Pliensbachian  and Forsey,  Liassic  (that  British Columbia.  ammonite  northern  Moreover,  concerning  Pliensbachian faunas of north-central Of  geology,  British Columbia was published  of both the N e w - and O l d Worlds (for example, Wiedenmayer,  the  work  western Cordillera and to recent publications on the taxonomy  Alarcon,  the general  fauna  for an updated revision on the status  prior to the widespread acceptance o f modern theories the  describe  ammonite  depositional history, and subsequent structural deformation of  Spatsizi Group. This study helps the Pliensbachian  A N D CONCLUSIONS  some of and  ammonites  145  were  found  i n the thesis area.  (Becheiceras)) fauna  found i n biogeographically related  on northern  Stikinia indicate  mixed Boreal/Tethyan Stratigraphic between  analysis  of  the ranges of certain  America have  that  ammonites  faunas  the entire  (Amaltheus  and  the  Spatsizi  area  fauna  genera i n Spatsizi  European  occupied  a position  shows  that  there  example,  are  Zonal standard, by which the Liassic  revised  zonal  standard  ibex and  exclusive  to  Pleuroceras  western  the  discrepancies  and the ranges o f the same genera as faunas  been traditionally been analyzed. This, together with  Tragophylloceras  within  times.  spinatum),  North  underlines  America,  such  of western  the presence i n  Spatsizi of Tethyan and East Pacific forms, and the absence of many Boreal (for  Liparoceras  from areas surrounding the Spatsizi  zone of the eastern Pacific region during Pliensbachian  listed i n the northwest North  However, Boreal  as  index genera  the  need  that  for  a  now being  developed by Smith et al. (in prep.). It should be noted here that although only the Pliensbachian area  was examined  Further of  i n this  work on the Toarcian  the  Pliensbachian/Toarcian  Jurassic paleontology The Group, (in  i n detail  rock  fauna  study,  a  rich  of the Spatsizi  boundary  would  publications. geologic  examined  stratigraphic  The Spatsizi of  was also  a  significant  precise  collected. delineation  contribution  to  Lower  and biostratigraphy of British Columbia.  sequence  history  fauna  Group and more  be  i n this  study  and is divided into the Joan, Eaglenest,  ascending  Toarcian  fauna of the Spatsizi  order).  These  Group provides  northern  Stikina,  is informally defined  Gladys, Groves,  units  will  be  an important and  the  use  of  and Walker  formalized  insight  into  in  i n the  rocks  Toarcian,  and Aalenian  of the  Spatsizi  ammonite  transgressions,  Group,  such  as  and the  Late  Toarcian  similar events on a regional and global scale. Further fossil collecting, and sedimentologic  the  Early  Mesozoic in  Geologic  events  Pliensbachian,  Early  regression,  exposure  forthcoming  biostratigraphy  correlate  detailed mapping, section  studies over the entire  Formations  the Lower  understanding the geology of the Spatsizi G r o u p has proven indispensable. recorded  as the Spatsizi  with  measuring,  of the Spatsizi Group,  146 in  order  geologic  to  determine  history  more  clearly  the  nature  of  the  stratigraphic  outlined in this thesis, would add considerably  complex Mesozoic history of north-central British Columbia.  to  the  relationships  and  knowledge of  the  BIBLIOGRAPHY Alarcon, J. C . B., 1983. Ammonites del Domerense de la Zona Subbetica (Cordilleras Breticas, Sur de Espana). P h . D . Thesis, University of Granada, Spain, 410 p., 16 p i . Anderson, R . G . , 1978. 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(eds.), The Ammonoidea; Systematics Association Special Volume, no. 18, p. 433-457.  APPENDIX  This appendix contains  print-outs of the  discussed in Chapter 1 (Introduction). single specimen. reproduced here, title  of  each  Data on all the each  1,  data  entered  into the  Each block of data represents  specimens  ammonite  database  the entry made for a  illustrated in this thesis  (pi. 1-11)  have  been  genus appearing i n the order i n which it appears i n the text. The  parameter,  Appendix-Figure  1  and  and a  the  detailed  groupings  into  description  Smith (in press).  157  of  which each  they of  are the  placed parameters  are is  shown  in  given  by  1 SUBORDER Taxonomy  Quantitative Morphology  2 5 8 11  4 SUBFAMILY 7 QUALIFIER 10 TAXAUTHYEAR 13 DMAX 20 WHD 27 BISPACE  32 37 42 47 52 57  15 D 22 WWD 29 SF  WHORL SHAPE USHOULD SULCI FURC SPROF CFORM  33 38 43 48 53 58  16 UD 23 WWWH 30 APPROX EXPANSION FLANKS PRIBD FURCPOS TUBERC APERTURE  3 FAMILY 6 SUBGENUS 9 SUBSPECIES 12 SYNONYMY 17 U 24 PRHW  34 39 44 49 54 59  18 EXP 25 SRHW  UWALL VENTER PTREND SRIBD UNITUBPOS SUTURE  35 40 45 50 55 60  19 WH 26 THW  UWALLHT VENTPROF PFORM STRENO CONSTRD ONTOGENY  Qualitative Morphology  31 36 41 46 51 56  Stratigraphy  61 STAGE 66 SUBZONE 7 1 DATUM  62 SUBSTAGE 67 HORIZON 72 RELDATUM  63 EURZONE 68 FORMATION 73 SITU  64 EURSUBZONE 69 MEMBER 74 ASSOCSPEC  70 LITHOLOGY  75 COUNTRY 81 SECTNO 86 REPOSITORY  76 PROVINCE 82 LOCNO 87 TYPE  77 LONG 83 OTHERNO 88 COLLECTORYR  78 LAT 79 Q 84 SUBLOCNO 89 GENERALOC  80 SECTNAME 85 SUPERLOCNO 90 SPECNO  Locality and Catalogue Information  Miscellaneous  91 92 93 94  FIGURE AP.l  VOLUTION UWALLANG KEEL PPROF SFORM CTREND  14 DPHRAG 21 WW 28 CHW  SUPERFAMILY GENUS SPECIES REFAUTHYEAR  REMARKS 1 REMARKS2 REMARKS3 REMARKS4  Parameters and parameter groupings of computer data used in this study.  65 ZONE  159  AMMONITINA  EODEROCERATACEAE  P O L Y M O R P H I T I N A E  UPTONIA  POLYMORPHITIDAE  SP. THOMSON  THOMSON  1 9 8 5  25  25  1 9 8 5  UPTONIA  38  9 . 5  S P .  '1.38  |7  I20 3  2  2  3  1  4  1  3  1  4  2'  3  4  2S5CP7  PLIENSBACHIAN  JAMESONI  LOWER  1-WbtJOLDI 2  SILTSTONE  JOAN TOODOGGONE  4 0  1  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  2  8 1 T D - S 3 - 4 B  139  8 1 T D - S 3 - 4 A  8 1 T D - S 3 - 4 C  G . S . C .  HOLOTYPE  T I P P E R  S P A T S I Z I  C - 9 0 9 2 6  0  1 9 8 1  A M M O N I T I N A  EODEROCERATACEAE  P O L Y M O R P H I T I N A E  UPTONIA  2  JOAN  LAKE  POLYMORPHITIDAE  SP. THOMSON  THOMSON  1 9 8 5  29 29  3 . 5  UPTONIA  1 9 8 5  29  1 1 . 5  | 4 0  12  41  122  DMAX.  D.  WW.  S P .  1 . 7 4  | 8 . 5  PRHW  3  2  2  3  1  4  1  3  1  4  2  .3  4  2S5CP7  P L I E N S B A C H I A N  LOWER  JAMESONI  FREBOLDI 2 SILTSTONE  JOAN TOODOGGONE  fi  1  a  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 5 1 A  6 4  G . S . C .  HOLOTYPF  THOMSON  19R3  A M M O N I T I N A  EODEROCERATACEAE  P O L Y M O R P H I T I N A E  OAYICERAS  2  JOAN  LAKE  C - 9 0 8 4 3 U  SPATSIZI  POLYMORPHITIDAE  SP. THOMSON  THOMSON  1 9 8 5  1 9 8 5  DAYICERAS  I  SP.  r  6 3 10  2  2 4  o  1  6  2  .  1R2CP5CP6  2 P L I E N S B A C H I A N  LOWER  JAMESONI  FREBOLDI  JOAN  SILTSTONE  TnnnnrcnnNF  4  1  0  CANADA  B.C.  128.5320  57.2915  1  GAT83-51A  64  G.S.C.  HOLOTYPE  THOMSON  1983  SPATSIZI  2  JOAN  LAKE  C-9C843Z  160  AMMONITIN/ POLYMORPH [TINAE SP. T H O M S O N 1<385  EODEROCERATACEAE DAYICERAS  POLYMORPHIFIDA£  THOMSON 1 9 8 5  DAYICERAS  I b  3 2  10 3  TOOOOGGONE CANADA 1  AMMONITINA  POLYMORPHITINAE SP. THOMSON 1 9 8 5  1R2CP5CP6  6  JOAN 1 128.5320 62 SMITH 1983  B.C. PLS:83A HOLOTYPE  G.S.C.  2  '  JAMtyUNI  LUWER  PLILNSUACHIAN  I 2 4  1  0 57.2915  FREBODTI— 2 SILTSTONE 2  POLYMORPHITIDAE  THOMSON 1 9 8 5  DAYICERAS  10 3  CANADA 2  Measurements  LOWER  B.C. PLS:83B HOLOTYPE not available  LAKE  PLS:83A  EODEROCERATACEAE  DAYICERAS  6  TnnnnRGnNE  JOAN  SPATSIZI  I  PLIENSBACHIAN  SP.  SP  I  3 2  2 4  1  6  JAMESONI JOAN 0 2 57.2915 128.5320 87 SPATSIZI SMITH 1 9 8 3 d u e t o fragmentary nature  2  1R2CP5CP6  FREBOLDI SILTSTONE 2  JOAN  LAKE  PLS:83B  of  specimen.  161  AMMONITINA  EODEROCERATACAEA  ACANTHOPLEUROCERATINAE  ACANTHOPLEUROCERAS  CF .  S T A H L I  (OPPEL  1 8 5 3 )  A.  THOMSON  5 0  42  1 9 . 5  1 6 . 7  54  7  31  POLYMORPHIDAE  4 5  11  C F .  STAHLI  113 17  I  1./B  7  WW 2  5  2  3  1  3  2  2  2  1  6  12  1 4  4  MLltNSUAtJHl AN  PINNAFORME 2  LUWtP.  J A M t b u N I  4  1  12  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  TOODOGGONE CANADA  B . C .  2  8 1 T D - S 3 -  G . S . C .  HYPOTYPE  JOAN  1 A  TIPPER  1 9 8 1  EODEROCERATACAEA ACANTHOPLEUROCERAS  CF .  S T A H L I  JOAN  43  POLYMORPHIDAE  A.  19  144  3 0  C F .  STAHLI  I  1.93  1 117 3  |17  2  6  1  3  2  3  3  2  2 2  1  6  12  4  4  MLILN5BACHIAN  LOWER  PINNAFORME 2  JOAN 4 B . C .  1  2  8 1 T D - S 3 - 1 A  137  G . S . C .  HYPOTYPE  TIPPER  128.5320  EODEROCERATACAEA  CF .  STAHLI  50  32  2  6  3  1  22 69  A.  12  11 a  1  '"PLIENSBACHIAN  C F . STAHLI 1 16 I 18  1.62  [4 4  2 3 2  4  I  3  2 2  6  JAME50NI  LUWbK  TOODOGGONE  B.C  G . S . C .  HYPOTYPE southwest  L o c a t e d  79TD-21-t-FA  3  m i l e s  of  b  1 128.5500 138 TIPPER 1979 l a c k Fox L a k e .  1 4 2R6KP7 PINNAFORME 2 LIMESTONE  JOAN!? ) CANADA  LAKE  POLYMORPHIDAE  THOMSON  22  1 1  JOAN  C-90930A  SPATSIZI  1 9 8 1  ACANTHOPLEUROCERAS  5 0  2  C - 9 0 9 2 9  AMMONITINA  1 8 5 3 )  SANDSTONE  12 57.2915  ACANTHOPLEUROCERATINAE (OPPEL  2R6KP7  JAMESONI  TOODOGGONE CANADA  LAKE  C-909SOB  S P A T S I Z I  THOMSON  43  2  C - 9 0 9 2 9  ACANTHOPLEUROCERATINAE 1 8 5 3 )  SANDSTONE  137  AMMONITINA  (OPPEL  2R6KP7  ir>  5 7 4 200 2 SPATSIZI  C-81970S  A M M O N I T I N /  k  EODEROCERATACAEA  ACANTHOPL! EUROCERATINAE S M I T H  POLYMORPHIDAE  L U N I N G I C E R A S PINNAFORME  198  THOMSON 1  L.  PINNAFORME  I  -  I  2  6  2  3  3  1  3  2  2  2  2R6CP7  3  6  6  2  5  6 P 7  3  2  LOWER  JAMESONI  12  1 4  .  2  "PLIENSBACHIAN  PINNAFORME  JOAN TOODOGGONE CANADA  B.C  .  G A T 8 3 G . S . C .  123B  u n a v a i l a b l e  0  1 2 9 . 0 0 0 0  5 7 . 3 0 0 0  2  130  HYPOTYPE  M e a s u r e m e n t s  SHALE  1  THOMSON d u e  t o  1983  f r a g m e n t a r y  A M M O N I T I N A  EODEROCERATACAEA  ACANTHOPLEUROCERATINAE  TROPIDOCERAS  S P A T S I Z I n a t u r e  C - 1 0 3 2 2 2  o f  s p e c i m e n .  POLYMORPHIDAE  SP. THOMSON  1985  THOMSON  4 8  48  1985  TROPIDOCERAS  27 120 DMAX.  D.  UD.  SP.  j  1 . 6 5 PRHW  2  5  2  3  4  1  3  4  6  2  2  2  1 4  4 2S3CR5CP7  PLIENSBACHIAN  LOWER  IBEX  FREBOLDI 2S I L T S T O N E  JOAN TOODOGGONE  12  1  n  CANADA  B . C .  1 2 9 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 4 B  2  G . S . C .  HYPOTYPE  THOMSON  2  JOAN  LAKE  G A T 8 3 - 4 C 1983  A M M O N I T I N A  EODEROCERATACEAE  ACANTHOPLEUROCERATINAE  TROPIDOCERAS  C - 1 0 3 3 0 4  S P A T S I Z I  POLYMORPHIDAE  SP. THOMSON  THOMSON  1985  2 1  4 6  1985  I  TonPTnnrFp<;  2  3  3  4  2  2  LOWER  2S3CR5CP7  IBEX  2-.. FREBOLDI  JOAN  SILTSTONE  i  n  CANADA  B . C .  1 2 9 . 5 3 2 0  1  GAT83- 1 AA  1  G . S . C . M e a s u r e m e n t s  44  a v a i l a b l e  d u e  t o  5 7 . 2 9 1 5  2  QP/l Tt; T 7 T  HYPHTYPF n o t  .  1  4  P L I E N S B A C H I A N  <;R._  f r a g m e n t a r y  n a t u r e  o f  JOAN J.AKE  r- mm s p e c i m e n .  1 i  163  AMMONITINA  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCERAS MUTICUM ( D ' O R B I G N Y  1 8 4 4 )  THOMSON  1 9 8 5  M.  MUTICUM 46  I  28  WH. 61  WW.  2  9  1  3  1  4  1 .  3  1  3  1  4  2P5  1  6  3  2 P L I E N S B A C H I A N  IBEX  LOWER  FREBOLDI  JOAN TOODOGGONE  46  CANADA  B . C .  2  81TD-• S 3 - 5 A  G . S . C . N e a r  t e c t o n l c a l 1 y  J o a n  L a k e  5 7 . 2 9 1 5  1 2 8 . 5 3 2 0 T I P P E R  c o m p r e s s e d  S e c t i o n  2  JOAN  LAKE  81TD - 3 S - 4 C  143  HYPOTYPE  S p e c i m e n  S I L T S T O N E 2  1 9 8 1  t h e r e f o r e  S P A T S I Z I  C - 9 0 9 2 4  m e a s u r e m e n t s  a r e  d i s t o r t e d .  4  A M M O N I T I N A  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCERAS MUTICUM ( D ' O R B I G N Y  1 8 4 4 )  39 28  9 . 5  4  THOMSON  39  19  24  8 6  1 9 8 5  M.  MUTICUM  1 . 4  4 9  11  | l 6  16  7  \  3  1  1  3  1  3  1  4  2P5  1  6  3  2  PLIENSBACHIAN  LOWER  IBEx1  FREBOLDI  JOAN CANADA G . S . C .  S I L T S T O N E  1  0  B . C .  1 2 8 . 5 6 10  5 7 . 2 8 5 5  G A T ( F ) 8 3 - 29A  1 12  HYPOTYPE  THOMSON  TOODOGGONE  A M M O N I T I N A  1 9 8 3  2  -  S P A T S I Z I  EODEROCERATACEAE  C - 9 0 8 2 3  EODEROCERATIDAE  METADEROCERAS MUTICUM ( D ' O R B I G N Y  1 8 4 4 )  6 0  THOMSON 6 0  DMAX.  152  I  '.-  1  MUTICUM  1.71  I  16  U D . E X 1P6.  1  2 4  M.  1 9 8 5  31  1  3  3 1  4  1  6  3P5  3 2 H L l t N S B A C H I A N  LOWER  IBEX  FREBOLDI  JOAN TOODOGGONE CANADA  B . C . 8 1 TD-S 6 -  G . S . C . N e a r  14-  HYPOTYPE J o a n  SILTSTONE  4  1  L a k e  Sect1 o n 4  1 2 8 . 5 6 10  5 7 . 2 8 5 5  14 1  8  T I P P E R  1 9 8 1  2  1TD-S 6 - 12  SPATS I 7 I  164  EODEROCERATACEAE  AMMONITINA  EODEROCERATIDAE  METADEROCERAS MUTICUM ( D ' O R B I G N Y  THOMSON  1 8 4 4 )  M.  1985  31  6 0  6 0  |  MUTICUM  1.96"  52  1  1  18  EXP  1  3  2  1 8  1  4  4  2P5  3  •  PLIENSBACHIAN  LOWER  IBEX  2 1-WbBULUl  JOAN  SILTSTONE 7  TOODOGGONE CANADA  12 B . C .  1  GAT(F  G . S . C .  HYPOTYPE  5 7 . 2 9 1 5  1 2 8 . 5 3 2 0 1 8 3 - 4 C  AMMONITINA  3 THOMSON  1983  JOAN  2  LAKE  G A T ( F ) 8 3 - 4 B  G A T 8 3 - 6 D  S P A T S I Z I  C - 1 0 3 3 0 5 A  EODEROCERATIDAE  EODEROCERATACEAE METADEROCERAS MUTICUM  ( D ' O R B I G N Y  THOMSON  1 8 4 4 ) 80  8 0  M.  1985  43  1 54  I  DMAX.  UD.  MUTICUM  2 . 25  1  I  18  18  EXP.  2  7  3  1  4  1  1  3  4 3  2P5  6 P L I E N S B A C H I A N  FREBOLDI 2 SILTSTONE  IBEX  LOWER  JOAN TOODOGGONE  12  CANADA  B . C .  1  GAT(F  G . S . C .  HYPOTYPE  7 5 7 . 2 9 1 5  128 . 5 3 2 0 1 8 3 - 4 C  GAT(F  3 THOMSON  1983  2  ) 8 3 - 4 B  S P A T S I Z I  JOAN  LAKE  G A T 8 3 - 6 D C - 1 0 3 3 0 5 B  !  165  AMMONITINA  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCERAS AFF .  MUTICUM  (D'ORBIGNY  1 8 4 4 )  THOMSON  9 0  9 0  1985  M.  55  I  23 DMAX. 1  2 3  1  A F F .  MUTICUM  6 1 D.  2 1  13  UD.  13 WH.  PR H W .  3  1  3 1  5  1  6  1R2CP6  4  PLIEN5BACHIAN  1  PINNAFORME  JAMESONI  LUWtK  SANDSTONE  JOAN CANADA  B . C . G A 0 8 3 - 4 B  G . S . C . R i b  l a r g e L o c a t e d  d e c r e a s e  5 7 . 4 3 5 0  .2  142  HYPOTYPE  d e n s i t y  0  2 1 2 9 . 1 0 3 0 0 ' B R I AN  w i t h  g r o w t h ,  a n d  1983 r i b s  S P A T S I Z I f a d e  o n  C-  l o w e r  103056  f l ank  o f  w h o r l s . 6  km  e a s t  o f  M t .  C a r t m e l .  AMMONITINA  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCERAS AFF . (D ' O R B I G N Y  MUTICUM THOMSON  1 8 4 4 )  1985  M.  A F F .  I 2 3  1  MUTICUM  I  1  3  1  3  1  3  1  5  1R2CP6  1  6  3  P L l L N b U A U H l A N TOODOGGONE  LUWtW  IBEX  FREBOLDI  JOAN  SILTSTONE  CANADA  15 B . C .  2 1 2 8 . 5 3 2 0  1  G A T 8 3 - 5 B  5  G . S . C .  HYPOTYPE  M e a s u r e m e n t s  n o t  THOMSON  a v a i l a b l e  d u e  t o  0 5 7 . 2 9 1 5 1 9 8 3  JOAN  S P A T S I Z I  f r a g m e n t a r y  n a t u r e  LAKE  C - 1 0 3 3 0 7 o f  s p e ci  m e n .  EOOEROCERATIDAE  EODEROCERATACEAE  AMMONITINA  2  METADEROCERAS MUTICUM  AFF . ( D ' O R B I G N Y  THOMSON  1844)  M.  1985  A F F . MUTICUM  I  I 2 3  1  1  3  "PLIENSBACHIAN TOODOGGONE CANADA 4 G . S . C . M e a s u r e m e n t s  LOWER  1  6  available  1 3 3P6  IBEX JOAN  30 B.C. GAT83-64A HYPOTYPE n o t  1  3 1 5  3  1 128.5610 104 THOMSON d u e  t o  1983  0 57.2855 2 GAT83-63B SPATSIZI  fragmentary nature  o f  FREBOLDI SILTSTONE JOAN LAKE GAT83-64B C-103108  specimen.  166  EODEROCERATACEAE  AMMONITINA  EODEROCERATIDAE  METADEROCERAS S I L V I E S I ( H E R T L E I N  THOMSON  1 9 2 5 )  1 9 8 5  S I L V I E S I  M.  75  150  150  | 5 0  2 . 1 5  43  28 D.  UO.  WH.  2  7  2  3  1  3  1  3  1  3  2  4  2P6  A  **>  1  6  1 P L I E N S B A C H I A N  LOWER  TOODOGGONE  34  CANADA  B . C .  1 2 8 . 5 7 3 0  G A S 8 3 - 10GC  98  IBEX  FREBOLDI  JOAN  G . S . C . R i b s  o n  HYPOTYPE i n n e r  a n d  SILTSTONE -0  I  STEEL  m i d d l e  w h o r l s  5 7 . 3 0 4 0  2  S P A T S I Z I  1 9 8 3  s t r a i g h t ,  r i b s  o n  o u t e r  C - 8 8 2 3 1 w h o r l s  m o r e  s 1 n u o u s .  METADEROCERAS S I L V I E S I ( H E R T L E I N  1 9 2 5 )  THOMSON  37  37  1 9 8 5  32  | WH.  2  S I L V I E S I  M.  147  18  I  1.38  10  I  14  14  PRHW  2 2  4  1  6  2P6  4 1  PLIENSSACHIAN  LOWE'R  TOnnnGGONF  30  1  CANADA  B . C .  1 2 8 . 5 3 2 0  G A T 8 3 - 8 B  19  HYPOTYPE  THOMSON 1983  IBEX  FREBOLDI  JOAN  1 G . S . C .  SILTSTONE  0 57.2915 GAT83-7B SPATSIZI  2  JOAN  LAKE  GAT83-7C C- 103324A  METADEROCERAS S I L V I E S I ( H E R T L E I N  THOMSON  1 9 2 5 )  M.  1 9 8 5  SILVIESI  I  I  2P6  PLIENSBACHIAN  LOWER  FREBOLDI SILTSTONE  TETET  -  JOAN TOODOGGONE CANADA 1 G . S . C . M e a s u r e m e n t s  1 128 . 5320 19 THOMSON 1983  30 B.C . GAT83-8B HYPOTYPE n o t  a v a i l a b l e  d u e  t o  f r a g m e n t a r y  JOAN LAKE GAT83-7C C-103324B  57,2915 GAT83-7B SPATSIZI n a t u r e  o f  s p e c i m e n .  167  A M M O N I T I N A  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCERAS CF .  MOUTERDI  (FREBOLD  THOMSON  1 9 7 0 )  44  44  1 9 8 5  21  M. 4 8  2 7  C F .  .73  1  :?  |11  2  1  3 4  MOUTERDI  1  2  3  3  1  1  3  4  3P6  1  6 1  FREBOLDI  P L I E N S B A C H I A N  LOWER  TOODOGGONE  23  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 5 D  7  G A T 8 3 - 5 C  G A T 8 3 - 5 E  S P A T S I Z I  C -  I B E X JOAN  G . S . C . R i b  HYPOTYPE  d e n s i t y  S I L T S T O N E  1  d e c r e a s e s  THOMSON  f r o m  A M M O N I T I N A  0  i n n e r  t o  1 9 8 3  m i d d l e  2  J O A N  L A K E  1 0 3 3 0 9  w h o r l s .  EODEROCERATACEAE  EODEROCERATIDAE  METADEROCEPAS CF .  MOUTERDI  ( F R E B O L D  THOMSON  1 9 7 0 ) 78  IB  1 9 8 5  43  M.  C F .  | 2 0 y 4  1  MOUTERDI  2 . 0 7  5 b  2 0 1  2  J  3  1  1  1  4  3P6  1  6 1  P L l t N b B A C H l A N  LUWtK  TOODOGGONE  8  CANADA  1  FREBOLDI  IBEX  S I L T S T O N E  JOAN  d e n s i t y  a g a i n  0  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  G A T 8 3 - 5 1 A  64  HYPOTYPE  G . S . C . R i b  1  o n  d e c r e a s e s  o u t e r  THOMSON  f r o m  i n n e r  t o  1 9 8 3  m i d d l e  2  S P A T S I Z I  whorls  JOAN  LAKE  C - 9 0 8 4 3 a  t h e n  i n c r e a s e s  w h o r l s .  A M M O N I T I N A  EODEROCERATIDAE  EODEROCERATACEAE METADEROCERAS  CF .  MOUTERDI  (FREBOLD  THOMSON  1 9 7 0 )  1 1 0 25  17  1 10  51  15  6 1  M.  1 9 8 5  D M A X .  |46 12 3 D .  C F . MOUTERDI .28 | 2 3  UD  2  7  2  3  1  4  1  3  1  1  1  4  3P6  1  6  3 1 P L I E N S B A C H I A N  LOWER  I B E X  FREBOLDI  JOAN TOODOGGONE CANADA 1 G . S . C . R i b  d e n s i t y  a g a i n  o n  o u t  «5 B C GAT83 -5B HVPOTvPE d e c - e a s e s from e r whorls  S I L T S T O N E  2 128.5320  57  2S  15  2  JOAN  LAKE  5  THOMSON 1 9 8 3 inner to m i d d l e  .it  3PATSIZI c r i s . then  C - 1 0 3 3 0 7  increases  EODEROCERATIDAE  EODEROCERATACEAE  A M M O N I T I N A  METADEROCERAS EVOLUTUM ( F U C I N I  THOMSON  1 9 2 1 )  31 6  29  31  16  19  67  M.  1985  EVOLUTUM  52  I  DMAX.  D.  In  13  U.  WH.  WW.  PRHW.  THW.  1  2  7  • 1  4  1  1  !i 1  1  4  1  6  3  3  P L I E N S B A C H I A N  2R6  (J I N N A t - U W M f c 2 LIMESTONE  JAME50N1/IHfcX  LOWER  J O A N ( ? ) TOpDOGGONE  G . S . C . F a i n t t h e  B . C .  1 2 8 . 5 5 0 0  7 9 T D - 2 1 4 - F A  138  HYPOTYPE  T I P P E R  i n t e r - r i b  s t r i a e  v e n t r o - 1 a t e r a l  L o c a t e d  3  1  1  CANADA  m i l e s  p r e s e n t  a n d  57.4266  C - 8 1 9 7 0 a  S P A T S I Z I  1979  j o i n  2  w i t h  t h e  nb s  p r i m a r y  a t  t u b e r c l e s .  s o u t h w e s t  o f  B l a c k  Fox  L a k e . EODEROCERATIDAE  EODEROCERATACEAE  A M M O N I T I N A  METADEROCERAS SP THOMSON  THOMSON  1985 53  53 26  1  I  1  1.70  53  1  j  20  SP.  U 20 1  3  2  2 3  METADEROCERAS  1985  28  3 2  4  3P6  3 1 P L I E N S B A C H I A N  LOWER  6  IBEX  2 PINNAf-uHMk  JOAN  SANDSTONE  m n n n G G n N E  1 1  2  0  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 4 A  1  G . S . C .  HYPOTYPE  THOMSON  1983  S P A T S I Z I  2  JOAN LAkE C - 1 0 3 3 0 3  '  EODEROCERATACEAE  AMMONITINA  EODEROCERATIDAE  DUBARICERAS FREBOLDI (FREBOLD  THOMSON  1970)  16  16  1985  DUBARICERAS  6  137  1 29  31  I  2.04  WH  2  3  3 1  29  1  3  3  1  4  4  1  6  1R2CP5CP6  2 FREBOLDI  PLIENSBACHIAN  LOWER  TOODOGGONE CANADA  47 B.C.  1 128.5320  5 7 . 2 9 1 5  2  GAT83-36A  79  GAT83-35A  G : S . C  HYPOTYPE  THOMSON  JOAN  AMMONITINA  FREBOLDI  1 6  SILTSTONE 1  1983  2  JOAN  LAKE  C-90836  SPATSIZI  EODEROCERATIDAE  EODEROCERATACEAE DUBARICERAS FREBOLDI  (FREBOLD  THOMSON  1970)  ™  1 1 2 1  3  1985  DUBARICERAS  I'  I  3 3  3  1  4  1  6  1  1R2CP5CP6  4  2 FREBOLDI  PLIENSBACHIAN  LOWER  TOODOGGONE CANADA  10 B.C.  2  3  GAT83-66D  96  G.S.C.  HYPOTYPE  THOMSON  JOAN  SILTSTONE 5 7 . 2 8 1 5  128.5610 1983  2  JOAN  LAKE  C-103118  SPATSIZI  EODEROCERATACEAE  AMMONITINA  FREBOLDI  5  EODEROCERATIDAE  DUBARICERAS FREBOLDI (FREBOLD  THOMSON  1970) 16  FREBOLDI  I  3 , WH,  DUBARICERAS  1985  WW J  3 1  4  1  6  1R2CP5CP6  4 2 PLIENSBACHIAN  LdWgR  TOODOGGONE CANADA  8  FREBOLDI JOAN  1 G.S.C.  B.C. GAT83-51 A HYPOTYPE  15 57.2915  2 128.5320  SILTSTONE  2  JOAN LAKE  64 THOMSON  1983  SPATSIZI  C-90843D  A M M O N I T I N A  EODEROCERATACEAE  EODEROCERATIDAE  DUBARICERAS FREBOLDI (FREBOLO  THOMSON  1 9 7 0 )  74 35  9  1985  DUBARICERAS  74  30  [43  12  35  C 4  I 34  2  7  3.  3  1  3  1  3  3  1  1 4  1  6  4  P L I E N S B A C H I A N  FREBOLDI,  126  2 . 1 5  1R2CP5CP6  LOWER  FREBOLDI 2 SILTSTONE  JOAN  TnqnnnanNF  37  1  1 1.  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  2  G A T 8 3 - 3 4 B  75  G A T 8 3 - 3 3 C  G A T 8 3 - 3 4 C  HYPOTYPE  THOMSON  S P A T S I Z I  C - 9 Q B 3 2 D  a  s  r.  A M M O N I T I N A  1983  EODEROCERATACEAE  2  JOAN  LAKE  EODEROCERATIDAE  DUBARICERAS FREBOLDI (FREBOLD  THOMSON  1 9 7 0 )  44  44  1985  DUBARICERAS  22 0.  2  7  3  3  1  3  2 . 52  |50 UD.  WH 1  3  1  4  1  6  1R2CP5CP6  4  PLIENSBACHIAN  2 FREBOLDI  LOWER JOAN  TOODOGGONE  t o  FREBOLDI  | 13  SILTSTONE  1  1  CANADA  B . C .  1 2 8 . 5 6 1 0  4  G A T 8 3 - 2 8 A  99  G . S . C .  HYPOTYPE  THOMSON  5 7 . 2 8 1 5 1983  S P A T S I Z I  2  JOAN  LAKE  C - 1 0 3  1  14  171  AMMONITINA  EODEROCERATACEAE  COELOCERATIDAE  REYNESOCOELOCERAS CF .  INCERTUM  ( F U C I N I  THOMSON  1 9 0 5 )  3 1 . 5  3 1 . 5  22  12  1985  38  171  |  WH, 1  13  R.  I60  19  15  SRHW,  CF.  R.  INCERTUM  1.37  7  30  15  WW  1 3  1  1  4  2P5 4  4  2  6  2  6P7CSC7PG  3  1  5  P L I E N S B A C H I A N  LOWER  I B E X / D A V O E I  3  -  1 FREBOLDI  JOAN TOODOGGONE  SILTSTONE  1  ?  CANADA  B . C .  1 2 8 . 5 6 1 0  5 7 . 2 8 5 5  4  8 1 T D - S 6 - 1 2  139  8 1 T D - S 6 - 1 4  8 1 T D - S 6 - 1  G . S . C .  HYPOTYPE  TIPPER  S P A T S I Z I  C - 9 0 5 2 6  R i b s  c h a n g e  f r o m  p r o r s l r a d l a t e  with  o n  I n c r e a s i n g  s h o r t  a n d  o u t e r  w h o r l s .  s t o u t  o n  1981 i n n e r  T u b e r c l e s  w h o r l s a r e  t o  2  JOAN  n a r r o w  r e d u c e d  i n  LAKE 1  a n d  s i z e  d i a m e t e r .  AMMONITINA  EODEROCERATACEAE  D A C T Y L I O C E R A T I D A E  AVEYRONICERAS SP.  A  THOMSON  1985  THOMSON  8 0  8 0 24  2 0  3 0  1985  AVEYRONICERAS  45  I  63  150  |  4 0  SP.  A  OMAX.D.UD.PRHW 2  3  1  .3  3  1  4  1  2  4  7  2 4  1P4CR7 IBEX JOAN 1  P L I E N S B A C H I A N  LOWER  TOODOGGONF  55  CANADA  B . C .  2  G A T 8 3 - 3 4 D  G . S . C . R i b s  o f  HOLOTYPE i n n e r  n o n - t u b e r c u 1  w h o r l s  a t e ,  t ub e r c u l a  l e s s  PINNAFORME 1 SILTSTONE  1  1 2 8 . 5 3 2 0 57.2915 77 THOMSON 1983 SPATSIZI t e . v e r y d e n s e : on o u t e r  SP.  LAKE  C-90834A who - I s  OACrYLIOCERATIOAE  A  THOMSON  1985  THOMSON  80  8 0  45  AVEYRONICERAS  1985 1  1  63  2  3  3  1  4  2  7 PLIENSBACHIAN TOODOGGONE CANADA 2 G . S . C . o f  i n n e r  n o n - t u b e r c u 1  a t  I  43  DMA X,D,UD.PRHW 1 3  R i b s  JOAN  de n s e .  EODEROCERATACEAE AVEYRONICERAS  AMMONITINA  2  2  4  IBEX JOAN 2 B . C 128.5320 57,2915 G A T 8 3 - 36B 80 P A R 4 T r PE THOMSON 1983 I S P A T S I Z I w h o r l s t u b e r c u l a t e . v e r y d e n s e ; on o u t e r e . less dense.  SP. A  1P4CR7  1 .PINNAFORME' SILTSTONE  LOWER  2  JOAN LAKE  C-90837 whorls  EODEROCERATACEAE  A M M O N I T I N A  D A C T Y L I O C E R A T I D A E  AVEYRONICERAS 8  SP. THOMSON  THOMSON  1985  1985  AVEYRONICERAS  I  1  3  2  3  4 2  4  1P4CR7  7  PL1LNSBACHIAS  LOWER  1  PlKINAFORMl  IBEX JOAN  '  TOODOGGONE  SILTSTONE  C  1  45  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  2  G A T 8 3 - 3 5 A  78  G A T 8 3 - 3 4 D  HOLOTYPE  THOMSON  G . S . C . R 1 b s  o f  I n n e r  w h o r l s  t u b e r c u l a t e ,  n o n - t u b e r c u l a t e ,  l e s s  M e a s u r e m e n t s  a v a i l a b l e  n o t  B  I  1  2  SP.  v e r y  1983  2  JOAN  S P A T S I Z I  d e n s e ;  o n  LAKE  G A T 8 3 - 3 6 A C - 9 0 8 3 5  o u t e r  w h o r l s  d e n s e .  A M M O N I T I N A  d u e  t o  f r a g m e n t a r y  n a t u r e  EODEROCERATIDAE  o f  s p e c i m e n .  I N D E T .  I N D E T . I N D E T . THOMSON 19  19  1985  8 . 2  37 2  4  2 1  A M M . G E N . E T . S P . I N D E T . 143  1  I  2 . 4 7  I  14  2  14 1  3 1  3  7  4  1 3  5  2R5  1 5  PLILN5BACHIAN  LOWER  FREBOLDI 2 SILTSTONE  JOAN 2  TOODOGGONE CANADA  8 B ..C .  .128 . 5 3 2 0  1  G A T 8 3 - 5 A  4  G . S . C .  HOLOTYPE  THOMSON  0 5 7 . 2 9 1 5 1983  S P A T S I Z I  2  JOAN  LAKE  C - 1 0 3 3 0 G  173  AMMONITINA  PSILOCERATACEAE  OX  YNOTICERATIDAE  FANNINOCERAS LATUM (MCLEARN  1 9 3 2 )  THOMSON  28  28  1985  FANNINOCERAS  6 . 5  23  . 5 6  Ma  41  LATUM  | 1 1 . 5  WH 4  3 2  3 2  4  2S4CR5CP7  5  1  P L l t N S B A i J H l AN  UPPtR  TOODOGGONE CANADA  7 0 B . C .  2  0  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  G A T 8 3 1 0 0 A ( F )  6 0  F A N N I N I EAGLENEST  1 G . S . C . S h o w s t o  HYPOTYPE c h a n g e  f i n e  d e n s e  I n  THOMSON  r i b b i n g  f a l c o i d  f r o m  r i b s  A M M O N I T I N A  a t  c o a r s e  SHALE  1983  s t r a i g h t  0 > 1 5 - 2 O  2  S P A T S I Z I r i b s  a t  iJOAN  LAKE  G A T - 1 0 0 A ( F s m a l l  d i a m e t e r s  mm.  PSILOCERATACEAE  OXYNOTICERATIDAE  FANNINOCERAS SP. THOMSON  27  1985  FANNINOCERAS  U  27  PRHW 4  SP.  I  3 3 2  4  4  1  PLILNSBACHIAN  UPPER  F A N N I N I EAGLENEST  TOODOGGONE CANADA  B . C .  4  8 1 T D - S 6 -  G . S . C . S h o w s t o  1  HYPOTYPE c h a n g e  f i n e  d e n s e  i n  r i b b i n g  f a l c o i d  0  1 2 8 . 5 6 1 0  5 7 . 2 8 1 5  136  8  THOMSON f r o m  r i b s  a t  SHALE  1  c o a r s e  1983  s t r a i g h t  D > 1 5 - 2 0  mm.  2  JOAN  LAKE  1 T D - S 6 - 2  S P A T S I Z I r i b s  a t  C - 9 0 5 1 5 F s m a l l  d i a m e t e r s  A M M O N I T I N A  HILDOCERATACEAE  A R I E T I C E R A T I D A E  A R I E T I C E R A S  H I L D O C E R A T I N A E  ALGOVIANUM (OPPEL  THOMSON  1 8 5 3 )  70  9  26  1 9 8 5  33  47  13  5 0  |22  DMAX.  D.  WH,  1  . 5 8  | 18  WW  3  1  3  3 4  14  2  2  2  6  ALGOVIANUM  A.  7 0  2  1 1 P3CR5KP7  4  P L I E N S B A C H I A N  2  FANNINI  UPPER JOAN  TOODOGGONE  SHALE  2  10  CANADA  B . C .  1 2 8 . 5 6  4  8 1 T D - S 6 - 1  136  G . S . C .  HYPOTYPE  T I P P E R  10  5 7 . 2 8 5 5  2  JOAN  LAKE  £ 1 T D - S 6 - 2 1 9 8 1  A M M O N I T I N A  HILDOCERATACEAE  A R I E T I C E R A T I D A E  A R I E T I C E R A S  S P A T S I Z I  C - 9 0 5 1 5 C  H I L D O C E R A T I N A E  ALGOVIANUM (OPPEL  1 8 5 3 ) 10.  THOMSON 5  1 9 8 5  A.  I  55  2  6  2  3  1  3  14  2  2  ALGOVIANUM  I" 3 4 2  1  3  4  1P3CR5KP7  PTTEN5BACHIAN  FANNINI  UPPER  2 SHALE  JOAN 1  TOODOGGONE CANADA  B . C .  1 2 8 . 5 6  4  8 1 T D - S 6 - 1  136  G . S . C .  HYPOTYPE  T I P P E R  10 £ 1981  AMMONITINA  HILDOCERATACEAE  A R I E T I C E R A T I D A E  A R I E T I C E R A S  10 57.2855 1TD-S6-2 SPATSIZI  2  JOAN LAKE C-90515A  HILDOCERATINAE  ALGOVIANUM (OPPEL  THOMSON  1 8 5 3 )  55  55  A,  1985  143 |19  2 3 . 5  36  ALGOVIANUM  120  2.62  WH  3 14  6  2  1 2  3  3 4 2  2  1  3  4  "PLIENSBACHIAN  1 P3CR5KP7 UPPER  F ANN INI 2SHALE  EAGLENEST TOODOGGONE  85  CANADA  B.C.  4  GAT83-65A HYPOTYPF  G . S . C .  1  128.56  10  107 THOMSON  57  2S55  S n i T <; r 7 r  2  JOAN LAKE r  -  im1 1 1  175  AMMONITINA ARIETICERATIDAE  H I L D O C E R A T I N A E  HILDOCERATACEAE A R I E T I C E R A S ALGOVIANUM  (OPPEL  THOMSON  1 8 5 3 )  6r5  6 5  A.  1 9 8 5  I  30  | DMAX,  22  D  2  3  3  1  3  4  14  2  2  2  2  ALGOVIANUM  3 . 3 2  46  1  1P3CR5KP7  4  2 F A N N I N I  ~PEIENSBACHIAN TIPPER  SHALE  J O A N ( ? ) 0  2  TOODOGGONE CANADA  B.C.  128  X  G A T 8 3 - 1 2 5 A  131  G . S . C .  HYPOTYPE  THOMSON  5 7 . 3 5 0 0  . 5 1 5 0  SECTION  2  G A T 8 3 - 1 2 5 B 1 9 8 3  A M M O N I T I N A  HILDOCERATACEAE  A R I E T I C E R A T I D A E  A R I E T I C E R A S  C - 1 0 3 2 2 3 A  S P A T S I Z I  H I L D O C E R A T I N A E  ALGOVIANUM (OPPEL  THOMSON  1 8 5 3 ) 37  37  A.  1 9 8 5  15  ALGOVIANUM  1 . 7 2  1 4 1  |  2  2  3  1  1P3CR5KP7  2  2 4  2  "PTIENSBACHIAN "UPPER  F A N N I N I SHALE  J O A N ( ? ) 2  0  CANADA  B . C .  1 2 8 . 5 1 5 0  5 7 . 3 5 0 0  X  G A T 8 3 - 1 2 5 A  131  G . S . C .  HYPOTYPE  THOMSON  TOODOGGONE  1 9 8 3  HILDOCERATACEAE  A R I E T I C E F  A R I E T I C E R A S  CF . (REYNES 47  C - 1 0 3 2 2 3 B  S P A T S I Z I  H I L D O C E R A T I N A E  RUTHENENSE THOMSON  8 6 8 )  32  6  47  W  13  4 0  1985  A. 1  I  Jh  \  21  3  6  2  3  4  1  3  4  6  2  2  3  1  RUTHENENSE  .S3  —re  3  4  P L I E N S B A C H I A N  SECTION G A T 8 3 - 1 2 5 B  A M M O N I T E 4A JATIDAE  2  2P6C7  r2 A N N i IM i  UPPER EAGLENEST  TOODOGGONF  85  2  CANADA  B . C .  1 2 8 . 5 6  4  G A T 8 3 - 6 4 C  106  HYPOTYPE  THOMSON  SHALE  ;  3  57.2555  10 1983  S P A T S I Z I  — 2 —  JUAN  L A K t  C - 1 0 3 1 1 0  -  A M M O N I T I N A  H I L D O C E R A T A C E A E  A R I E T I C E R A T I D A E  A R I E T I C E R A S  C F  .  H I L D O C E R A T I N A E  R U T H E N E N S E  ( R E Y N E S  T H O M S O N  1 8 6 8 )  5 6 3 8  7  .  5  3  1 9 8 5  A .  2 1  5 0 1 5  1 4 2  I  3 9  6  1  R U T H E N E N S E 1 9  . 6 2  I  2 3  2  3  4  1  3  4  6  2  2  3  1 3  ;  2 P 6 C 7  4  2 P L I E N S B A C H I A N  F A N N I N I  U P P E R E A G L E N E S T  T O O D O G G O N E  8 5  C A N A D A  B . C .  1 2 8 . 5 6  4  G A T 8 3 - 6 7 A  1 0 8  G . S . C .  H Y P O T Y P E  S H A L E  2  0 1 0  5 7 . 2 8 5 5  T H O M S O N  1 9 8 3  A M M O N I T I N A  H I L D O C E R A T A C E A E  A R I E T I C E R A T I D A E  L E P T A L E O C E R A S  C F  P S E U D O R A D I A N S  .  ( R E Y N E S  1 8 6 8 )  T H O M S O N  3 8 . 5  3 8  .  C -  L A K E  1 0 3 1 2 0  H I L D O C E R A T I N A E  L . 1 4 4  3 4  J O A N  S P A T S I Z I  1 9 8 5  1 7  5  2  C F .  1 .  P S E U D O R A D I A N S  7 8  1 3  | 2 6 W H  3  2  4  1  3  1  3  3 P 4 C R 5 C P 7  3 2  4  2 P L I E N S B A C H I A N  U P P E R  F A N N I N I E A G L E N E S T  T O O D O G G O N E  8 0  C A N A D A 1 G . S . C .  S H A L E  2  0  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  G A T 8 3 - 1 3 B  2 7  G A T 8 3 - 9 B  H Y P O T Y P E  T H O M S O N  1 9 8 3  A M M O N I T I N A  H I L D O C E R A T A C E A E  A R I E T I C E R A T I D A E  L E P T A L E O C E R A S  C F  P S E U D O R A D I A N S  .  ( R E Y N E S  T H O M S O N  1 8 6 8 )  3 3 W H  1 4  L A K E  C - 1 0 3 3 3 2  H I L D O C E R A T I N A E  L . 1  4 9  I  2 5  1 .  C F .  P S E U D O R A D I A N S  3 7  1 3  2  3  1  1  3  4  3  2  2  3  3 P 4 C R 5 C P 7  3 4  J O A N  S P A T S I Z I  1 9 8 5  1 9  3 9  3 9  2  4  2 P L I E N S B A C H I A N  F A N N I N I  U P P E R  S H A L E  E A G L E N E S T  0  T O O D O G G O N E  9 0  1  C A N A D A  B . C .  1 2 8 . 5 6  4  81TD - S 6 -  G . S . C .  H Y P O T Y P E  1  1  5 7 . 2 8 5 5  1 0  2  J O A N  L A K E  3 6  T H O M S O N  1 9 8 3  S P A T S I Z I  C - 9 0 5 1 5 D  A M M O N I T I N A  HILDOCERATACEAE  A R I E T I C E R A T I D A E  LEPTALEOCERAS  CF. (REYNES  H I L D O C E R A T I N A E  PSEUDORADIANS 18G8)  THOMSON  3 1 . 5  3 1 . 5  1985  L.  14  144  35  CF.  2 . 3  PSEUDORADIANS | 1 1  |27 WH  3 4  1  14  2  3  3  2  2  3  1  3P4CR5CP7  4  PLIENSBACHIAN  1 F A N N I N I  UPPER EAGLENEST  SHALE  2  TOODOGGONE CANADA  B . C .  1 2 8 . 5 1 5 0  5 7 . 3 5 0 0  X  G A T 8 3 - 1 2 5 B  132  G A T 8 3 - 1 2 5 A  G A T 8 3 - 1 2 6 A  S P A T S I Z I  C - 1 0 3 2 2 4  G . S . C .  HYPOTYPE  I n n e r m o s t  w h o r l s  s m o o t h  0  THOMSON t o  D = 7  1983  HILDOCERATACEAE  A R I E T I C E R A T I D A E  LEPTALEOCERAS  (REYNES  H I L D O C E R A T I N A E  PSEUDORADIANS 1 8 6 8 )  THOMSON  28  25  L.  1985  10  |40  36  CF.  OMAX. 4  1  14  D.  WH.  9  PRHW  2  3  3  2  2  3  1  3P4CR5CP7  4  P L I E N S B A C H I A N  1 F A N N I N I  UPPER EAGLENEST  SHALE  TOODOGGONE  8 0  1  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 1 4 A  29  G A T 8 3 - 9 B  I n n e r m o s t  psFimnPAnTAMt;  I  1 .62  l25  3  G . S . C .  SECTION  mm.  A M M O N I T I N A  CF .  2  HYPOTYPE w h o r l s  s m o o t h  0  THOMSON t o  D = 7  mm.  1983  S P A T S I Z I  2  JOAN C-  LAKE  103335  178  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  H I L D O C E R A T I D A E  PROPINQUUM ( W H I T E A V E S  THOMSON  1 8 8 G )  3 2 . 5  32 . 5  1 9 8 5  L.  9  4 5  PROPINQUUM  UH  •J..  |15  33  I 1 4 . S  /U  j  SRHW 4  2  4  1  12 3  2  4R5CPS  3  P L I E N S B A C H I A N  UPPER  TOODOGGONE  9 8  CANADA 1 G . S . C .  J  J  3  2  1  4  3P4CR5CP6  4  2  4  T  1  4  1  S e c o n d a r y  r i b s  .  PWOPINUUUM EAGLENEST  SHALE  1  17  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  G A T 8 3 - 9 9 A  55  HYPOTYPE  THOMSON  b e c o m e  a t  p r i m a r y  2  JOAN LATE™ G A T 8 3 - 9 9 D  1983  U D = 7 . 5  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  mm.  S P A T S I Z I R i b b i n g  f a d e s  C - 1 0 3 2 0 3 A a t u u > i u mm.  H I L D O C E R A T I D A E  PROPINQUUM ( W H I T E A V E S  THOMSON  1 8 8 6 )  38 . 5  38 . 5  1 9 8 5  L.  1 2 . 5  PROPINQUUM  1 . 6 0  | 3 2 . 5  | 1 3 . 5  35 3  2  2  3  1  4  1  3  2  4  12  2 P L I E N S B A C H I A N  PROPINQUUM  UPPER J O A N ( ? )  Tnnnnr;r:nNF  CALC.SHALE 10  2  CANADA  B . C .  1 2 8 . 5 1 5 0  5 7 . 3 5 0 0  Y  G A T 8 3 - 1 2 5 B  132  G A T 8 3 -  HYPOTYPE  THOMSON  fi  s  r.  1983  AMMONITINA  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  2  125A  S P A T S I Z I  SECTION G A T 8 3 -  126A  C - 1 0 3 2 2 4 B  HILDOCERATIDAE  PROPINQUUM ( W H I T E A V E S  THOMSON  1 8 8 6 )  59  59  1985  19  L. PROPINQUUM 2. 7 25  |32  I  42 4  2  3  4  1  3  3 2  1 4  12  P L I E N S B A C H I A N  UPPER EAGLENEST  TOODOGGONE CANADA  X G . S . C .  B C G i ? : - 1 25B HYFCTV^E T  2 128.5150 132 THOMSON 1 9 8 3  10 57 3500 2 GM33-125A SPATSIZI  2 PROPINQUUM CALC.SILTS SECT ION GA783-126A C - * 03 2 24 A  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  H I L D O C E R A T I D A E  PROPINQUUM ( W H I T E A V E S  THOMSON  1 8 8 6 )  L.  1 9 8 5  PROPINQUUM |  8  36  2 2  |  3  2  2  3  1  4  1  3  2  4  12  2  PLIENSBACHIAN  UPPER  PROPINQUUM J O A N ( ? )  C A L C . S H A L E  TOODOGGONE  95  2  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 9 9 B  56  G A T 8 3 - 1 3 A , B  G . S . C .  HYPOTYPE  THOMSON  0  1 9 8 3  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  ( W H I T E A V E S  THOMSON  2  JOAN ,C  LAKE  G A T 8 3 - 14A  S P A T S I Z I  C - 1 0 3 2 0 4 C  H I L D O C E R A T I D A E  PROPINQUUM 1 8 8 6 ) 33  33  L.  1 9 8 5  10  PROPINQUUM  | 3 0  39 D, 3  2  2  4  1  3  WH  U D ,  3 2  1 .  4  12  2 PROPINQUUM  P L I E N S B A C H I A N  UPPER  TnnnnGGONE  95  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 9 9 B  56  GAT83- 1 3 A . B . C  G A T 8 3 -  HYPOTYPE  THOMSON  SPATSIZI  C - 1 0 3 2 0 4 D  J O A N ( ? )  G.S  C  CALC.SHALE  0  2  1 9 8 3  AMMONITINA  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  2  JOAN  LAKE 14A  HILDOCERATIDAE  PROPINQUUM ( W H I T E A V E S  49  4 9  I  THOMSON 1 9 R 5  1 8 8 6 )  14  P R O P TWO! II IM  I  | 2 9  2 0  41  UD 2  3  1  4  3 2  2 3  1 4  12  2  P L I E N S B A C H I A N  PROPINQUUM  UPPER J O A N ( ?  )  TnnnnccnMC CANADA  B.C.  1 2 8 . 5 3 2 0  1  G A T 8 3 - 9 9 B  56  MVPDTYPF  THOMSON I P S ' !  ri  c  r  n  57 2915 2 GAI8 3 - 1 3 A . B . C s P A r s i 71  CALC.SHALE JOAN  LAKE  GAT83-14A  r-in^704F  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  H I L D O C E R A T I D A E  PROPINQUUM ( W H I T E A V E S  THOMSON  1 8 8 6 )  1 9 8 5  L.  1 1  46  4 6  PROPINQUUM  |24  11 s  2.54  4 1  4  2  3  3  1  4  1  3  2  4  12  2  TlIENSBAcHIAN  PRoPINotlUM '  UPPER EAGLENEST  TnnnntiGONE  SHALE  1  0 5 7 . 2 9 1 5  CANADA  B . C .  1 2 8 . 5 3 2 0  1  GAT83-13B  27  G . S . C .  HYPOTYPE  THOMSON  1 9 8 3  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  SP.  2  S P A T S I Z I  UOAN C-  LAKE  1 0 3 3 3 2  H I L D O C E R A T I D A E  A  THOMSON  1 9 8 5  THOMSON  51.5  5 1 . 5  1 9 8 5  15  L I O C E R A T O I D E S 2 . 0 4  129  1  41  SP.  A  | 2 1  19  3  2  2  3  1  4  1  3  4  4  12  2  1  3  3  3P4CR5CP6  PL I ENSBAUHTAiM  '  PROP1W6UUM 2  UMMbW EAGLENEST  TOODOGGONE  95  CANADA  B . C .  128.5320  1  G A T 8 3 - 9 9 B  56  G . S . C .  HOLOTYPE  THOMSON  SHALE  2  1983  A M M O N I T I N A  HILDOCERATACEAE  HARPOCERATINAE  L I O C E R A T O I D E S  SP . THOMSON  0 57.2915 2 GAT83- 13A, B SPATSIZI  LAKE  GAT83-14A  C-103204A  HILDOCERATIDAE  B 1 9 8 5  THOMSON  43  45  LIOCERATOIDES SP. B  1985  13  42  3  2  2  1 2  3  I"  DO M  4  1  1  3. 4 4  3  1 4 3P4CR5CP5  P L I E N S B A C H I A N  UPPER  PROPINQUUM 2S H A L E  EAGLENEST  TnnnrjGGONF CANADA 1  G S  UOAN  C.  B C GA FS3-99B HOLOTYPE  2  128.5320 56 THOMSON 1 9 8 3  0 5 7 . 2 9 15 2 GAT 8 3 - 13A. 8 SPATSIZI  JOAN LAKE GAT83-14A C-103204B  A M M O N I T I N A  HARPOCERATINAE ( W H I T E A V E S  1886)  32  32 43 2 1  4 4 12  HILDOCERATACEAE LIOCERATOIDES PROPINQUUM THOMSON 1985 7.5 |23  HILDOCERATIDAE L. PROPINQUUM 2.37 | 14 3 2  3 3  1  4 "PLIENSBACHIAN  UPPER  TOODOGGONE CANADA 1  B.C. GAT83-100A HYPOTYPE  G.S.C.  EAGLENEST 2 128.5320 60 THOMSON 1983  AMMONITINA  HILDOCERATACEAE  HARPOCERATINAE  PROTOGRAMMOCERAS  PROPINQUUM SHALE 2  15 57.2915  2  JOAN LAKE GAT83-100A  SPATSIZI  H I L D O C E R A T I D A E  PALTUM (BUCKMAN  1 9 2 2 )  THOMSON 95  95  P.  1 9 8 5  27  I  I  43 DMAX,  D.  28 5 0  UD.  WH.  3  3 1  4  3  6  PALTUM  j  1 . 8 9  3  1  2  4  4  2  2  1R2CP4KP7  PLIEN5BACHIAN  PROPINQUUM 1 SHALE  UPPER EAGLENEST  TOODOGGONE CANADA  92  EX  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 15  1  G A T 8 3 - 9 9 B  56  G A T 8 3 -  G . S . C . R i b  HYPOTYPE  d e n s i t y  v a r i e s  w i t h  0  THOMSON  HILDOCERATACEAE PROTOGRAMMOCERAS THOMSON 68  DMAX. •  P.  1 9 8 5  18  44 D.  I  26  |  4 6 UD.  3  3 1  4  6  C - 1 0 3 2 0 4 P  3  PALTUM  1.81  |  3 0  !HW  WH.  PC  3  1  2  4  4  2  2  1 R2CP4KP7  P L I E N S B A C H I A N  PROPINQUUM 1 SHALE '  UPPfcW EAGLENEST  0  92 B . C .  EX  CANADA  1 2 8 . 5 3 2 0  57  1  G A T 8 3 - 9 9 B  56  GAT83- 1 3 A SPAPSIZ i  TOODOGGONE  G . S . C . R i b  LAKE  HILDOCERA TIDAE  A M M O N I T I N A  1 9 2 2 )  JOAN  SPAPSIZI  1983  HARPOCERATINAE (BUCKMAN  2  13A  g r o w t h .  PALTUM •  4 1  PF !HW  d e n s i t y  HYPOTYPE with  v a r i e s  THOMSON growth.  1983  2 9 1 5  2  JOAN LAKE C-103204Q  1  AMMONITINA  HILDOCERATACEAE  HARPOCERATINAE  PROTOGRAMMOCERAS  H I L D O C E R A T I D A E  PALTUM (BUCKMAN  THOMSON  1 9 2 2 )  P.  1 9 8 5  PALTUM  I 3  3  4  1  3  3  1  2  4  4  2  €  I  2  1R2CP4KP7  PLTENSBAcHIAN  UPPER  PROPINQUUM 1 SHALE  EAGLENEST EX  TOODOGGONE  0  CANADA  B . C .  1 2 8 . 5 3 2 0  5 7 . 2 9 1 5  1  G A T 8 3 - 1 0 0 A  6 0  G A T 8 3 - 1 3 A  G . S . C . R 1 b  density  HYPOTYPE  vanes  w i t h  THOMSON g r o w t h .  1 9 8 3  S P A P S I Z I  2  JOAN  LAKE  G A T - 1 0 0 A ( P  183  APPENDIX LOCALITY  2  DATA  S E C T I O N 1 L O C A T JTTF.S: See fig. M A P for position of Section 1; see fig. S E C 1 for position of localities in Section 1.  LOCALITY* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41  NOTEBOOK* GAT(F)83-4A GAT(F)83-4B GAT(F)83-4C GAT(F)83-5A GAT(F)83-5B GAT(F)83-5C GAT(F)83-5D GAT(F)83-5E GAT(F)83-6A GAT(F)83-6B GAT(F)83-6C GAT(F)83-6D GAT(F)83-6E GAT(F)83-6F GAT(F)83-7A GAT(F)83-7B GAT(F)83-7C GAT(F)83-8A GAT(F)83-8B GAT(F)83-8C GAT(F)83-9A GAT(F)83-9B GAT(F)83-11A GAT(F)83-11B GAT(F)83-12A GAT(F)83-13A GAT(F)83-13B GAT(F)83-13C GAT(F)83-14A GAT(F)83-15B GAT(F)83-16C GAT(F)83-18C GAT(F)83-19B GAT(F)83-20A GAT(F)83-21A GAT(F)83-21B GAT(F)83-22B GAT(F)83-22C GAT(F)83-22D GAT(F)83-23A GAT(F)83-23B  G.S.C.# C-103303 C-103304 C-103305 C-103306 C-103307 C-103308 C-103309 C-103310 C-103314 C-103315 C-103316 C-103317 C-103318 C-103319 C-103320 C-103321 C-103322 C-103323 C-103324 C-103325 C-103326 C-103327 C-103329 C-103331 C-103330 C-103328 C-103332 C-103325 C-103335 C-103339 C-103333 C-103348 C-103350 C-90805 C-90806 C-90826 C-90808 C-90809 C-90810 C-90811 C-90812  IN SITU • • •  •  EX SITU  •  •  •  • •  •  •  • •  • •  * * *  •  • *  • • •  *  • *  • • •  • *  •  • *  •  • • •  • *  COMMENTS  184  LOCALITY* 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61  NOTEBOOK # GAT(F)83-23C GAT(F)83-23D GAT(F)83-23E GAT(F)83-23F GAT(F)83-24A GAT(F)83-24B GAT(F)83-25A GAT(F)83-26A GAT(F)83-27A GAT(F)83-27B GAT(F)83-110A GAT(F)83-110B GAT(F)83-111B GAT(F)83-99A GAT(F)83-99B GAT(F)83-99C GAT(F)83-99D GAT(F)83-99E GAT(F)83-100A GAT(F)83-100B  G.S.C.* C-90813 C-90814 C-90815 C-90822 C-90816 C-90817 C-90818 C-90819 C-90820 C-90821 C-103213 C-103215 C-103214 C-103203 C-103204 C-103205 C-103206 C-103207  IN  SITU *  • •  EX SITU  *  • •  •  *  • • *  C-90839  SECTION 1 VTCTNTTY:  • • • • •  Belemnite  • • • •  The following localities are positioned close to, but not directly on the Section 1. See fig. M A P for exact position of each of the following localities.  LOCALITY* 62  NOTEBOOK.*  G.S.C. *  63  GAT(F)83-43A  C-90839  64  GAT(F)83-51A  C-90843  65  GAT(F)83-51B  C-90844  *  66  GAT(F)83-51C  C-90845  *  PLS:83-A  IN SITU *  EX S I T U  *  line  COMMENTS  of  Collected by D r . P . L . Smith, 1983, lower siltstones of Unit 1, approx. 150m east of lake. Collected from lower siltstones of U n i t 1, 100m west of Section 1. Collected from lower siltstones of U n i t 1, 250m east of Section 1. Collected just below Unit 5 near eastern nose of anticline. Collected from U n i t 5 float, just above loc. 65.  LOCALITY* 67  NOTEBOOK* GAT(F)83-51D  G.S.C* C-90846  68  GAT(F)83-51E  C-103112  69  GAT(F)83-51F  TN STTU  EX STTU COMMENTS * Collected from Unit 3 • Collected from Unit 3 * Nautiloid from Unit 5  EX STTU COMMENTS  SECTION 7. LOCAT JTIES: LOCALITY* 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85  NOTEBOOK* GAT(F)83-32A GAT(F)83-33A GAT(F)83-33B GAT(F)83-33C GAT(F)83-34A GAT(F)83-34B GAT(F)83-34C GAT(F)83-34D GAT(F)83-35A GAT(F)83-36A GAT(F)83-36B GAT(F)83-37A GAT(F)83-37B GAT(F)83-38A GAT(F)83-42A GAT(F)83-47A  G.S.C* C-90827 C-90828 C-90829 C-90830 C-90831 C-90832 C-90833 C-90834 C- 90835 C-90836 C-90837 C-90841 C-90842 C-90838 C-90840 C-90847  TN STTU  86  GAT(F)83-49A  C-90848  •  87  PLS:83-B  •  •  • •  • • • • •  • •  *  • *  • *  *  Collected from contact between Units 3 & 5, in cirque 200m north of Section 2. Collected from limestone bed in Ashman Fm., on ridge 200m west of loc.85. Collected by Dr. Paul Smith from the lower siltstones of Unit 1.  186  SECTION 3 LOCALITIES; LOCALITY* 88 89 90  NOTEBOOK* GAT(F)83-55A GAT(F)83-56A GAT(F)83-58A  G.S.C* C-103101 C-103102 C-103102  I N SITU  EX SITU  COMMENTS  IN  EX  COMMENTS Collected from U n i t 5 about 300 west o f section 3. Collected from U n i t 1 i n creek gully 300m east of Section 3. As for loc. 92 As for loc. 92 As for loc. 92 As for loc. 92 As for loc. 92 As for loc. 92; collected by M r . J. Steel, 1983.  SECTION 3 VICINTTY:  LOCALITY* 91  NOTEBOOK* GAT(F)83-53A  G.S.C* C-90849  92  GAT(F)83-54A  C-90850  93 94 95 96 97 98  GAT(F)83-54C GAT(F)83-66B GAT(F)83-66C GAT(F)83-66D GAT(F)83-66E GAS(F)83-106C  C - 103113 C - 103116 c- 103117 C - 103118 c- 103119 c- 88231  SITU  SITU *  SECTION 4 LOCALITIES LOCALITY*  NOTEBOOK*  99 100 101 102 103 104 105 106 107 108 109 110 111  GAT(F)83-28A GAT(F)83-62A GAT(F)83-62B GAT(F)83-63A GAT(F)83-63B GAT(F)83-64A GAT(F)83-64B GAT(F)83-64C GAT(F)83-65A GAT(F)83-67A GAT(F)83-68A GAT(F)83-69A GAT(F)83-69B  G.S.C*  •  CCCCCCCCCCCCC-  103114 103104 103105 103106 103107 103108 103109 103110 103111 103120 103122 103123 103124  I N SITU  EX SITU  COMMENTS  187  112  GAT(F)83-29A  C-90823  •  113  GAT(F)83-29B  C-90824  *  From Unit 200m east section 4. From Unit 200m east section 4.  1, of 5, of  188  OTHER LOCALITIES  NORTH  E N D OF JOAN TAKE: The following localities are from M i d d l e to Upper Toarcian near the north end of Joan Lake (fig. M A P ) .  LOCAT J T Y # 114 115 116 117 118  NOTEBOOK # GAT(F)83-70A GAT(F)83-71A GAT(F)83-71B GAT(F)83-72A GAT(F)83-72B  G.S.C. # C-103125 C-103126 C-103127 C-103128 * C-103129  TN S I T U  EX  mudstones  of U n i t 2,  STTU *  • • • *  WEST  E N D OF ANTICLINE: The following localities were found in the area west of the westernmost of volcanic rocks in the thesis map area. See fig. M A P for exact positions.  G.S.C. #  119  NOTEBOOK* GAT(F)83-102A  120 121 122 123 124  GAT(F)83GAT(F)83GAT(F)83GAT(F)83GAT(F)83-  102B 102C 103A 105A 113A  C - 103219 C - 103219 c- 103211  125 126 127 128 129  G A T ( F ) 8 3 - •113B G A T ( F ) 8 3 - 113C G A T ( F ) 8 3 - 114A G A T ( F ) 8 3 - 114B G A T ( F ) 8 3 - •123A  c- •103217 c- 103218 c- 103219 c- •103220 c- •103221  130  G A T ( F ) 8 3 - •123B  c- •103222  LOCALITY #  C-103218  c-  103216  IN SITU *  • • * *  •  *  EX  SITU  exposure  COMMENTS Collected from U n i t 5. As for loc. 119. As for loc. 119. F r o m U n i t 4. F r o m Ashman F m . From Unit 2, apparently resting directly on Toodoggone Volcanics. As for loc.124. As for loc.124. As for loc.124. As for loc.124. From a Lower Pliensbachian inlier 1.5km nortwest of westernmost volcanics. From a Lower Pliensbachian inlier 1.5 km northwest of westernmost volcanics.  189  S E C T I O N X I.OCAITTTF.S: The Plateau Section is located 10 k m north of the thesis map area and is underlain by Upper Pliensbachian/Lower Toarcian strata (fig. 1.1). The seqence consists of U n i t 1 siltstones (Upper Pliensbachian) overlain by shales and tuffaceous shales of Early Toarcian age (fig. 2.10).  LOCALITY * 131 132 133 134  GEOLOGICAL  NOTEBOOK * GAT(F)83-125A GAT(F)83-125B GAT(F)83-126A GAT(F)83-126B  SURVEY  OF  G.S.C # C-103223 C-103224 C-103225 C-103226  CANADA:  1981  IN SITU  135  NOTEBOOK*  G.S.C* C-87245  136  C-90515  137  C-90930  138  C-81970  139 140  C-90926 C-90526  141 142 143  C-90527 C-103056 C-90924  COMMENTS  LOCALITIES  The following localities were examined by D r . Survey of Canada during the field season of 1981.  LOCALITY*  E X SITU  H . W.  IN SITU  EX  Tipper  SITU  of  the  Geological  COMMENTS  Just west of loc. 139. Vicinity of Section 4; Upper Pliensbachian. Vicinity of Section 2; Lower Pliensbachian. Southwest of Black Fox Lake; Lower Pliensbachian siltstones interbedded in volcanics. Section 2 vicinity. Vicinity of Section 4. As for loc. 140. As for loc. 138. As for loc. 139.  MISCELLANEOUS LOCALITIES; LOCALITY* 144  NOTEBOOK* GAT(F)83-1AA  G.S.C* C-103311  IN SITU  EX  SITU *  COMMENTS  Found in volcanic core of anticline.  190  [All Fig.  1,  2.  Uptonia  EXPLANATION OF PLATE 1 figures natural size unless otherwise indicated] sp.  l a . C-90843u; latex cast of external mould from locality 64. l b . Internal mould. X2 l c . Latex cast of external mould. Id. Internal mould. 2a, b. C-90926; internal mould from locality 139. X2 2c, d. Specimen number and locality as for figure 2a, b. Fig.  3.  Dayiceras  sp.  3a, b. PLS:83B; internal mould from locality 87. X2 3a, d. Specimen number and locality as for figure 3a, b.  X2  192  [All Fig.  1, 2.  Dayiceras  EXPLANATION OF PLATE 2 figures natural size unless otherwise indicated.] sp.  l a , b. C-90843x; internal mould from locality 64. X2 l c , d. Specimen number and locality as for figure l a , b. 2a, b. P L S : 8 3 A ; Fig.  3-5.  Acanthopleuroceras  latex cast of external  cf. A. stahli  mould from locality 62.  (OPPEL)  3. C-90930b; latex cast of external mould from locality 137. 4. C-81970s; internal mould from locality 138. 5. C-90930a; latex cast of external mould, locality as for figure 3.  194  [All Fig.  1.  EXPLANATION OF PLATE 3 figures natural size unless otherwise indicated]  Luningiceras  pinnaforme  SMITH  C-103222; internal mould from locality 130. Fig.  2, 3.  Tropidoceras  sp.  2. C-103304; internal mould from locality 2. 3. C-103311; latex cast o f external Fig.  4, 5.  Metaderoceras  muticum  mould from locality 144.  (D'ORBIGNY)  4. C-90823; internal mould from locality 112. 5. C-90527; latex cast of external  mould from locality 141.  196  [All Fig.  1-3.  EXPLANATION OF PLATE 4 figures natural size unless otherwise indicated.]  Metaderoceras muticum ( D ' O R B I G N Y ) 1. C-90924; internal mould from locality 143. 2. C-103305a; latex cast of external mould from locality 3. 3. C-103305b; internal mould from locality 3.  198  [All Fig.  1-3.  EXPLANATION O F PLATE 5 figures natural size unless otherwise indicated.]  Metaderoceras aff. M. muticum ( D ' O R B I G N Y ) 1. C-103307; internal mould from locality 5. 2. C-103056; internal mould from locality 142. 3. C-103108; latex cast of external mould from locality 104.  Fig.  4, 5.  Metaderoceras cf. M. moulerdi ( F R E B O L D ) 4. C-103309; latex cast of external mould from locality 7. 5a. C-90843a; internal mould from locality 64. 5b. Specimen number and locality as for figure 5a; latex external mould.  cast of  200  [All Fig.  1.  EXPLANATION O F PLATE 6 figures natural size unless otherwise indicated.]  Metaderoceras  cf.  M.  mouterdi  (FREBOLD)  l a , c. C-103307; internal mould from locality 5. l b . Specimen number and locality as for l a , c; external mould. Fig.  2.  Metaderoceras  sp.  C-103303; latex cast of extremal Fig.  3.  Metaderoceras  C-81970; Fig.  4, 5  Metaderoceras  evolutum  mould from locality 1.  (FUCINI)  internal mould from locality 138. silviesi ( H E R T L E I N )  4. C-103324a; latex cast of externasl  mould from locality 19.  5. C-103324b; internal mould from locality 19. Fig. 6.  latex  Ammonite gen. et sp. indet. C-103306; internal mould from locality 4.  cast  of  SO/  202  [All Fig. 1.  EXPLANATION O F PLATE 7 figures natural size unless otherwise indicated.]  Metaderoceras silviesi ( H E R T L E I N ) C-88231; latex cast of external  Fig. 2-4.  mould from locality 98.  Dubariceras freboldi D O M M E R G U E S , M O U T E R D E , and R I V A S 2a, b. C-103118;  internal  mould from locality 96.  3. C-90836; latex cast o f external mould from locality 79. 4. C-103114; latex cast of external mould from locality 99.  204  [All Fig.  1.  EXPLANATION OF PLATE 8 figures natural size unless otherwise indicated.] cf. R. incertum  Reynesocoeloceras  (FUCINI)  C-90526; internal mould from locality Fig.  2.  Aveyroniceras  sp.  B  C-90835; latex cast of exernal Fig.  3, 4.  Dubariceras  140.  mould from locality  DOMMERGUES,  freboldi  78.  M O U T E R D E , and R I V A S  3a. C-90832d; latex cast of external mould from locality 75. 3b. Specimen number and locality as for figure 3a; internal mould. 4. C-90843; latex cast of external mould from locality 64. Note; ribs projecting strongly onto venter. Fig.  5,  6.  Aveyroniceras  sp.  A  5a. C-90834a; internal mould from locality 77. 5b. Specimen number and locality as for figure 5a; external mould. 6. C-90837; internal/external mould from locality 81.  latex  cast  of  206  [All Fig.  1.  EXPLANATION OF PLATE 9 figures natural size unless otherwise indicated.]  Fanninoceras  latum  McLEARN  100A(F); latex cast of external Fig.  2.  Fanninoceras  sp.  C-90515; internal Fig.  3-6.  mould from locality 60.  Leptaleoceras  cf.  3. C-103332;  L.  mould from locality 136.  pseudoradians  (REYNES)  latex cast of external  4. C-103335; latex cast of external 5. C-103224; latex cast of external 6. C-90515d; latex cast of external Fig.  7-11.  .  Arieticeras  7. 8. 9. 10. 11.  algovianum  mould from locality 27. mould from locality 29. mould from locality 132. mould from locality 136.  (REYNES)  C-103223a; latex cast of external mould from locality 131. C-90515c; internal mould from locality 136. C-90515a; internal mould from locality 136. C-103223b; latex cast of external mould from locality 131. C-103111; latex cast of external mould from locality 107.  208  [All Fig.  1, 2.  E X P L A N A T I O N O F P L A T E 10 figures natural size unless otherwise indicated.]  Arieticeras  cf.  A.  ruthenense  (REYNES)  1. C-103120; latex cast of external 2. C-103110; latex cast of external Fig.  3-8.  Lioceratoides  propinquum  mould from locality 108. mould from locality 106.  (McLEARN)  3. C-103203; latex cast of external mould from locality 55. 4. C-103332; latex cast of external mould from locality 27. 5. C-103204e; latex cast o f external mould from locality 56. 6. C-103204d; latex cast o f external mould from locality 56. 7a. C-10322a4; internal mould from locality 132. 7b. Specimen number and locality as for figure 7a; latex cast of external mould. 8. C-103224b; latex cast of external mould from locality 56. Note occurrence with Protogrammoceras paltum.  SO?  210  EXPLANATION OF PLATE 11 [All figures natural size unless otherwise indicated.] Fig.  1.  Lioceratoides  sp. A  C-103204a; latex cast of external mould from locality 56. Fig.  2.  Lioceratoides  sp. B  C-103204b; latex cast of external mould from locality 56.. Fig.  3-5.  Protogrammoceras  paltum  (BUCKMAN)  3. 100A(P); latex cast of external mould from locality 60. C-103204p; latex cast of external mould from locality 56. C-103204q; latex cast of external mould' from locality 56.  />tf/$L/a?T7o?J5 (coo -r)  J^/?<^ /^LfQOT&LOfr  oTTAcxJ/f  c  Y  /gOfc&W/lt  Jyt//3/a*J  ?  AX-fr  rf&tas/OfL.  A&O&CTS, .45£?ytfT7tvO  

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